What is the Latin word for ill-nature?

The usual Latin words for “ill-nature” are malevolentia, malignitās, malitia. The right choice depends on the sense; see the distinctions below.

English → Latin

“ill-nature” in Latin

malevolentiamalevolence, hatred, dislike, envy malignitāsspite, malice, malignity; stinginess, niggardliness, meanness malitiaa bad quality; badness, wickedness; spite, malice, ill will; an act of malice; cunning, artfulness

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

ill-nature

malevolentia (ill-will against another): malignitas (selfish feeling that grudges anything good to any but one’s self): malitia (= “versuta et fallax nocendi ratio,” Cic., κακία): malevolens ingenium (Plaut.): malefici mores (Id.): acerbitas morum (with immanitas naturae, Cic.): acerbitas naturae (Cic.; sourness, etc., of temper).

Quick answer

What is the Latin word for ill-nature?: The usual Latin words for “ill-nature” are malevolentia, malignitās, malitia. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.