Word Origin & History
defendmid-13c., from O.Fr. defendre, from L. defendere "ward off, protect," from de- "from, away" + fendere "to strike, push." In the Mercian hymns, L. defendet is glossed by O.E. gescildeð.
undefended1564, "not defended, unprotected," from
un- (1) "not" + pp. of
defend (v.). Attested earlier in a now-obsolete sense of "unforbidden" (1399).