1. Ab Initio – From the beginning.

2. Actionable per se – The very act is punishable, and no proof of damage is required.

3. Actio personalis moritur cum persona – A personal right of action dies with the person. In other sense, if he dies, the right to sue is gone.

4. Actori incumbit onus probandi – The burden of proof is on the plaintiff.

5. Actus me invito factus non est mens actus – An act done by me against my will is not my act. Read with section 94 of IPC.

6. Actus non facit reum nisi mens sit rea – An act does not make one guilty unless it is accompanied by a guilty mind.

7. Actus reus – Guilty act.

8. Actus Reus Non Facit Reum Nisi Mens Sit Rea – Conviction of a crime requires proof of a criminal act and intent. Or an act does not make a defendant guilty without a guilty mind. Or an act does not constitute guilt unless done with a guilty intention.

9. Ad hoc – For the particular end or case at hand.

10. Alibi – At another place, elsewhere.

11. Amicus Curiae – A friend of court or member of the Bar who is appointed to assist the court.

12. Ante Litem Motam – Before suit brought; before controversy instituted, or spoken before a lawsuit is brought.

13. Assentio mentium – The meeting of minds, i.e. mutual assents.

14. Audi alteram partem – No man shall be condemned unheard.

15. Bona fide – In good faith.

16. Bona vacantia – Goods without an owner.

17. Boni judicis est ampliare jurisdictionem – It is the part of a good judge to enlarge his jurisdiction, i.e. remedial authority.

18. Caveat – A caution registered with the public court to indicate to the officials that they are not to act in the matter mentioned in the caveat without first giving notice to the caveator.

19. Caveat actor – Let the doer beware.

20. Caveat emptor – Let the buyer beware.

21. Caveat venditor -Let the seller beware.

22. Certiorari – A writ by which orders passed by an inferior court is quashed.

23. Communis hostis omnium – They are common enemies of all. The common enemy of everyone. Read with section 4(2) of IPC.

24. Corpus – Body.

25. Corpus delicti – The facts and circumstances constituting a crime and Concrete evidence of a crime, such as a corpse (dead body).

Also, it refers to the principle that ‘a crime must be proved to have occurred before a person can be convicted of committing that crime.’ (This definition is mostly used in Western Law.)

26. Crimen trahit personam – The crime carries the person. Read with section 2 of IPC. In other words, it means wherever a person goes, and if he commits a crime there, then he will be covered by the provisions of the Indian Penal Code, that is, Interterritorial Jurisdiction.

27. Damnum sine injuria – Damages without injuries.

28. De facto – In fact.

29. De jure – By law.

30. De minimis – About minimal things.

31. De Minimis Non Curat Lex – The law does not govern trifles (unimportant things). Or law is not concerned with small or insignificant things/matters. Read with section 95 of IPC. Or A common law principle whereby judges will not sit in judgment of extremely minor transgressions (offence, wrongdoings) of the law.

32. De novo – To make something anew.

33. Dictum – Statement of law made by the judge in the course of the decision but not necessary to the decision itself.

34. Doli capax – Capable of forming necessary intent to commit a crime. Read with section 83 of IPC.

35. Doli incapax – Incapable of crime. Or incapable of forming the intent to commit a crime. Read with section 82 of IPC.

36. Detinue – Tort of wrongfully holding goods that belong to someone else.

37. Donatio mortis causa – Gift because of death. Or a future gift given in expectation of the donor’s imminent death and only delivered upon the donor’s death.

38. Estoppel – Prevented from denying.

39. Ex gratia – As favour.

40. Ex officio – Because of an office held.

41. Ex parte – Proceedings in the absence of the other party.

42. Ex post facto – Out of the aftermath. Or after the fact.

According to Wikipedia, It is a law that retroactively changes the legal consequences (or status) of actions that were committed or relationships that existed before the enactment of the law. In criminal law, it may criminalise actions that were legal when committed; it may aggravate a crime by bringing it into a more severe category than it was in when it was committed; it may change the punishment prescribed for a crime, as by adding new penalties or extending sentences; or it may alter the rules of evidence in order to make conviction for a crime likelier than it would have been when the deed was committed.

43. Fatum – Beyond human foresight.

44. Factum probans – Relevant fact.

45. Fraus est celare fraudem – It is a fraud to conceal a fraud.

46. Functus officio – No longer having power or jurisdiction.

47. Furiosi nulla voluntas est – Mentally impaired or mentally incapable persons cannot validly sign a will, contract, or form the frame of mind necessary to commit a crime. Or a person with mental illness has no free will.

48. Furious absentis loco est – A madman is like one who is absent. Read with section 84 of IPC.

49. Furiosis furore suo puiner -A madman is best punished by his own madness.

50. Furiosis nulla voluntas est – A madman has no will.

51. Habeas corpus – A writ to have the body of a person to be brought in before the judge.

52. Ignorantia facit doth excusat, Ignorance juris non-excusat – Ignorance of fact is an excuse, but ignorance of the law is no excuse. Read with sections 76 and 79 of IPC.

53. Ignorantia juris non excusat – Ignorance of law is not an excuse. Or ignorance of the law excuses no one. In other words, a person who is unaware of a law may not escape liability for violating that law merely because one was unaware of its content.

54. Injuria sine damnum – Injury without damage.

55. Ipso facto – By the mere fact.

56. In promptu – In readiness.

57. In lieu of – Instead of.

58. In personam – A proceeding in which relief I sought against a specific person.

59. Innuendo – Spoken words that are defamatory because they have a double meaning.

60. In status quo – In the present state.

61. Inter alia – Among other things.

62. Inter vivos – Between living people (especially of a gift as opposed to a legacy).

63. Interest Reipublicae Ut Sit Finis Litium – It means it is in the interest of the state that there should be an end to litigation.

64. Jus cogens or ius cogens – Compelling law.

65. Jus in personam – Right against a specific person.

66. Jus in rem – Right against the world at large. Related: What Is Right in Rem and Right in Personam?

67. Jus naturale – Natural law. Or in other words, a system of law based on fundamental ideas of right and wrong that is natural law.

68. Jus Necessitatis – It means a person’s right to do what is required for which no threat of legal punishment is a dissuasion.

Dissuasion means the action or process of trying to persuade someone not to take a particular course of action.

Question asked by a law student: I have a doubt about the maxim jus necessitatis. Does it come under section 81 or 87 of IPC?
Answer: This is called the doctrine of necessity. It means a person doing a thing under compulsion of a situation. It is not considered a wrongful act. It comes under the ambit of section 81 of IPC.

69. Jus non scriptum – Customary law.

70. Jus scriptum – Written law.

71. Jus – Law or right.

72. Justitia nemini neganda est – Justice is to be denied to nobody.

73. Jus soli – Right of soil.

74. Jus sanguins – Right of blood or descent.

75. Lex non a rege est violanda – The law must not be violated even by the king.

76. Locus standi – Right of a party to an action to appear and be heard by the court.

77. Mala fide – In bad faith.

78. Malum in se or Mala in se (plural) – Wrong or evil in itself. Or Mala in se is ‘a term that signifies crime that is considered wrong in and of itself.’ For example, most human beings believe that murder, rape, and theft are wrong, regardless of whether a law governs such conduct or where the conduct occurs and is thus recognisably malum in se.

79. Malum prohibitum – In a way, opposite of Malum in se. It means ‘crimes are criminal not because they are inherently bad, but because the act is prohibited by the law of the state.’ For example, jurisdiction in India requires drivers to drive on the left side of the road. This is not because driving on the right side of a road is considered immoral, but because the law says to drive on the left side and not on the right side.

80. Mandamus – ‘We command’. A writ of command issued by a higher court to government and public authority to compel the performance of public duty. Related: 5 Types of Writs.

81. Mens rea – Guilty mind.

82. Misnomer – A wrong or inaccurate name or term.

83. Modus operandi – Way of working. Or mode of operation.

84. Modus Vivendi – Way of living.

85. Mutatis Mutandis – With the necessary changes having been made. Or with the respective differences having been considered.

86. Nemo bis punitur pro eodem delicto – Nobody can be twice punished for the same offence.

87. Nemo debet bis vexari pro una et eadem causa – It means no man shall be punished twice for the same offence.

88. Nemo debet esse judex in propria causa or Nemo judex in causa sua or Nemo judex in sua causa – Nobody can be the judge in his own case.

89. Nemo moriturus praesumitur mentire – A man will not meet his maker (God) with a lie in his mouth. Or, in other words, ‘no man at the point of death is presumed to lie.’ This maxim is related to dying declaration.

90. Nemo Potest esse tenens et dominus – Nobody can be both a landlord and a tenant of the same property.

91. Nolle prosequi – A formal notice of abandonment by a plaintiff or prosecutor of all or part of a suit.

92. Novation – Transaction in which a new contract is agreed by all parties to replace an existing contract.

93. Nullum crimen sine lege, nulla poena sine lege – There must be no crime or punishment except in accordance with fixed, predetermined law. In other words, there must be no punishment without law.

94. Nunc pro tunc – Now for then. A ruling nunc pro tunc applies retroactively to correct an earlier ruling.

95. Non Sequitur – A statement (such as a response) that does not follow logically from or is not clearly related to anything previously said.

Source: Merriam Webster Dictionary.

96. Obiter dictum – Things said by the way. It is generally used in law to refer to an opinion or non-necessary remark made by a judge. It does not act as a precedent.

In other words, Obiter dictum means “that which is said in passing,” an incidental statement. Specifically, in law, it refers to a passage in a judicial opinion that is not necessary for the decision of the case before the court. Such statements lack the force of precedent but may nevertheless be significant.

Source: Britannica

97. Onus probandi – Burden of proof.

98. Pacta Sunt Servanda – Agreements must be kept. Or Agreements are legally binding.

In international agreements it means ‘every treaty in force is binding upon the parties to it and must be performed by them in good faith.’

99. Pari passu – With an equal step. Read more about it on Wikipedia.

100. Particeps criminis – A participator in the actual crime/partner in crime.