n. & v.
--n.
1. a any of several medieval military expeditions made by Europeans to recover the Holy Land from the Muslims. b a war instigated by the Church for alleged religious ends.
2 a vigorous campaign in favour of a cause.
--v.intr. engage in a crusade.
Derivatives:
crusader n.
Etymology: earlier croisade (F f. croix cross) or crusado (Sp. f. cruz cross)