1580s, variant form of ambush
(q.v.); a reborrowing of a Fr. word after it had been Italianized; from Fr. embuscade (16c.), Gallicized from It. imboscata, lit. "a hiding in the bush," compounded from the same elements as O.Fr. embuscher. Sometimes ambuscado, with faux Sp. ending popular in Eng. 17c.