Lewis & Short

mălĕfăcĭo (or separately, mălĕ fă-cio), fēci, factum, 3, v. n. [male-facio], to do evil, harm, mischief to any one, to injure: alicui, Plaut. Mil. 2, 2, 11: neque tu verbis solves umquam, quod mi re male feceris, Ter. Ad. 2, 1, 10: tibi, Vulg. 1 Reg. 26, 21.
With contra: malefacere omnia contra aliquem, Vulg. Jer. 38, 9.
Hence, mălĕfactum (or separately, mălĕ factum; sync., malfactum, Plaut. Trin. 1, 2, 185; v. Ritschl, Opusc. 2, p. 720 sq.), i, n., an evil deed, injury: benefacta male locata malefacta arbitror, Enn. ap. Cic. Off. 2, 18, 62 (Trag. v. 429 Vahl.): augere, Cic. Inv. 2, 36, 108.