noun

1. any of the military expeditions which Christians undertook from the 11th to the end of the 13th cent. to recover the Holy Land from the Muslims
2. a vigorous, concerted action for some cause or idea, or against some abuse

Etymology: < Sp cruzada, altered after Fr croisade, both < ML cruciata < pp. of cruciare, to mark with a cross < L crux, cross

intransitive verb crusaded -·sad′ed, crusading -·sad′·ing