"deliberate killing of oneself," 1651, from Mod.L. suicidium "suicide," from L. sui "of oneself (gen. of se "self"), from PIE *s(u)w-o- "one's own," from base *s(w)e- (see idiom) + -cidium "a killing" (see -cide). Probably an Eng. 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-L., the term for "one who commits suicide" was felo-de-se, lit. "one guilty concerning himself."
http://www.etymonline.com/index.php?term=suicide
Etymology
http://www.etymonline.com/index.php?term=suicide
Etymology