1725, from homicide + -al (1), or from Late Latin homicidalis. Related: Homicidally. As an adjective, homicidious is from 1630s.
Entries linking to homicidal
homicide n.
"the killing of another person," early 13c., from Old French homicide, from Latin homicidium "manslaughter," from homo "man" (see homunculus) + -cidium "act of killing," from caedere "to kill, to cut down" (from PIE root *kae-id- "to strike").
The meaning "person who kills another" (late 14c.) also is from French (homicide), from Latin homicida "a murderer," from homo + -cida "killer." Identical in French and English, the two words differ in Latin and in other languages (for example, Spanish homicida/homicidio).
-al 1
suffix forming adjectives from nouns or other adjectives, "of, like, related to, pertaining to," Middle English -al, -el, from French or directly from Latin -alis (see -al (2)).