"misuse of power, wrongful exercise of lawful authority or improper performance of a lawful act," 1590s, from French mesfaisance, from mesfaisant, present participle of Old French mesfaire "to misdo," from mes- "wrongly" (see mis- (2)) + faire "to do," from Latin facere "to make, do, perform" (from PIE root *dhe- "to set, put"). Related: Misfeasor.
*dhē-, Proto-Indo-European root meaning "to set, put."
It forms all or part of: abdomen; abscond; affair; affect (v.1) "make a mental impression on;" affect (v.2) "make a pretense of;" affection; amplify; anathema; antithesis; apothecary; artifact; artifice; beatific; benefice; beneficence; beneficial; benefit; bibliothec; bodega; boutique; certify; chafe; chauffeur; comfit; condiment; confection; confetti; counterfeit; deed; deem; deface; defeasance; defeat; defect; deficient; difficulty; dignify; discomfit; do (v.); doom; -dom; duma; edifice; edify; efface; effect; efficacious; efficient; epithet; facade; face; facet; facial; -facient; facile; facilitate; facsimile; fact; faction (n.1) "political party;" -faction; factitious; factitive; factor; factory; factotum; faculty; fashion; feasible; feat; feature; feckless; fetish; -fic; fordo; forfeit; -fy; gratify; hacienda; hypothecate; hypothesis; incondite; indeed; infect; justify; malefactor; malfeasance; manufacture; metathesis; misfeasance; modify; mollify; multifarious; notify; nullify; office; officinal; omnifarious; orifice; parenthesis; perfect; petrify; pluperfect; pontifex; prefect; prima facie; proficient; profit; prosthesis; prothesis; purdah; putrefy; qualify; rarefy; recondite; rectify; refectory; sacrifice; salmagundi; samadhi; satisfy; sconce; suffice; sufficient; surface; surfeit; synthesis; tay; ticking (n.); theco-; thematic; theme; thesis; verify.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit dadhati "puts, places;" Avestan dadaiti "he puts;" Old Persian ada "he made;" Hittite dai- "to place;" Greek tithenai "to put, set, place;" Latin facere "to make, do; perform; bring about;" Lithuanian dėti "to put;" Polish dziać się "to be happening;" Russian delat' "to do;" Old High German tuon, German tun, Old English don "to do."
"wrongful conduct, the doing of that which ought not to be done," especially "official misconduct, violation of a public trust or obligation," 1690s, from French malfaisance "wrongdoing," from malfaisant, from mal- "badly" (see mal-) + faisant, present participle of faire "to do," from Latin facere "to do" (from PIE root *dhe- "to set, put").
[S]pecifically, the doing of an act which is positively unlawful or wrongful, in contradistinction to misfeasance, or the doing of a lawful act in a wrongful manner. The term is often inappropriately used instead of misfeasance. [Century Dictionary]
Malfeasor "wrong-doer" is attested from early 14c. Related: Malfeasant.