word-forming element meaning "away, from, from off, down," denoting disjunction, separation, departure; from Latin ab (prep.) "off, away from" in reference to space or distance, also of time, from PIE root *apo- "off, away" (also the source of Greek apo "off, away from, from," Sanskrit apa "away from," Gothic af, English of, off; see apo-).
The Latin word also denoted "agency by; source, origin; relation to, in consequence of." Since classical times usually reduced to a- before -m-, -p-, or -v-; typically abs- before -c-, -q-, or -t-.
"deliberate killing of oneself," 1650s, 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; much maligned by Latin purists because it "may as well seem to participate of sus, a sow, as of the pronoun sui" [Phillips]. The meaning "person who kills himself deliberately" is from 1728. In Anglo-Latin, the term for "one who commits suicide" was felo-de-se, literally "one guilty concerning himself."
Even in 1749, in the full blaze of the philosophic movement, we find a suicide named Portier dragged through the streets of Paris with his face to the ground, hung from a gallows by his feet, and then thrown into the sewers; and the laws were not abrogated till the Revolution, which, having founded so many other forms of freedom, accorded the liberty of death. [W.E.H. Lecky, "History of European Morals," 1869]
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. Suicide blonde (one who has "dyed by her own hand") first attested 1921. Baseball suicide squeeze is attested from 1937.