1590s, "act of doing or producing evil," from French maleficence or directly from Latin maleficentia "an evildoing, mischievousness, injury," from maleficus "wicked" (see malefic). Sense of "malefic character" is by 1796.
Proto-Indo-European root meaning "false, bad, wrong." The exact sense of the root remains uncertain, "since it concerns a collection of largely isolated words in different IE branches" [de Vaan].
It forms all or part of: blame; blaspheme; blasphemous; blasphemy; dismal; mal-; malady; malaise; malaria; malediction; malefactor; malefic; malevolence; malevolent; malice; malicious; malign; malison; malversation; mauvais.
It is the hypothetical source of/evidence for its existence is provided by: Avestan mairiia‑, "treacherous;" Greek meleos "idle; unhappy;" Latin male (adv.) "badly," malus (adj.) "bad, evil;" Old Irish mell "destruction;" Armenian mel "sin;" Lithuanian melas "lie," Latvian malds "mistake," possbily also Greek blasphemein "to slander."