1.  a. An act of witchcraft performed with the intention of causing damage or injury; the resultant harm; (also) the power of Satan (rare). Now hist.

?1613    G. Abbot in T. B. Howell Compl. Coll. State Trials (1816) II. 795,   I hope that those, who have embraced the gospel, should be free from this maleficium. 

1908    Mod. Lang. Notes Mar. 84/1   The ‘maleficium’ consists in the pact with the devil and the submission to his sovereignty.

1930    Mod. Lang. Notes Apr. 258   The broadspread human belief in maleficium—‘the working of harm to the bodies and goods of one’s neighbours by means of evil spirits or strange powers derived from intercourse with such spirits’.

1963    N. E. Whitten in A. Dundes Mother Wit (1973) 404/1   Maleficia refer to misfortunes, attributed to evil.

1964    Jrnl. Hist. Ideas 25 342   The anxious ecclesiastical authorities could think of but one cause as relevant to all this disorder, this bad Faith, significantly labelled ‘maleficium’, the power of the Evil one himself.

1980    N. & Q. Apr. 151/1   The implication of the plea of maleficium in the divorce proceedings was that Essex had been bewitched by some unknown external agency.

1991    Shakespeare Q. 42 328   The witches plot to cause the magical kinds of harm to others conventionally associated with witches’ maleficium: interference with livestock, weather, and male sexuality. 

 b. A potion or poison, used esp. in witchcraft.

1965    J. T. Noonan Contraception 156   Pseudo-Bede asks: ‘Have you drunk any maleficium [L. bibisti ullum maleficium], that is, herbs or other agents so that you could not have children?’ (Pseudo-Bede, ‘The Order for Giving Penance,’ 30). In this sentence maleficium is not the sterilizing magical act, but the sterilizing magical potion.

1996    Nature 31 Oct. 782/2   Insidious anti-heroines worm their way into the homes of respectable America and then, witch-like, callously fill them with maleficium, poisoning family relations and even the dessert. 

 2. Civil Law. An act of wrongdoing which causes harm, injury, or loss to another party; the result of such an act.

1830    U.S. Rep. (U.S. Supreme Court) 28 231   ‘Barratry must be some breach of trust in the master ex maleficio’, in which, I presume, maleficium must mean some wilful and injurious act.

1944    All Eng. Law Rep. 1 658   Assuming the section to be one of a penal nature, a lex poenalis, it is a little odd to find it applied in cases where there is neither delictum nor maleficium.

1969    Jrnl. Amer. Hist. Oct. 200   Massachusetts law developed the concept, as did English law, that, while witchcraft itself might be punishable, condemnation ordinarily occurred only if maleficium—a harmful act—was perceived.

1992    N.Y. Rev. Bks. 28 May 42/1   Witchcraft without a proven element of maleficium seems to have been regarded as harmless.

Pronunciation:  Brit.  /malᵻˈfɪʃɪəm/ , /ˌmalᵻˈfɪkɪəm/ , U.S. /ˌmæləˈfɪʃiəm/ , /ˌmɑləˈfɪʃiəm/

Inflections:  Plural maleficia.

Etymology:  < classical Latin maleficium evil deed, injury, sorcery (the latter sense is increasingly common from Apuleius (late 2nd cent.) onwards, especially in phrase maleficium magicum) < maleficus (see malefic adj.) + -ium-y suffix4.