suicide(n.)
1650s, "deliberate killing of oneself," from Modern Latin suicidium "suicide," from Latin sui "of oneself" (genitive of se "self"), from PIE *s(u)w-o- "one's own," from root *s(w)e- (see idiom) + -cidium "a killing," from caedere "to slay" (from PIE root *kae-id- "to strike").
Probably an English coinage; the word was much maligned by Latin purists because it "may as well seem to participate of sus, a sow, as of the pronoun sui" [Phillips, "New World of Words," 1671].
The meaning "person who kills himself deliberately" is attested from 1728. In Anglo-Latin, the term for "one who commits suicide" was felo-de-se, literally "one guilty concerning himself." It was used occasionally as a verb 19c.
In England, suicides were legally criminal if of age and sane, but not if judged to have been mentally deranged. The criminal ones were mutilated by stake and given degrading burial in highways until 1823.