crusader

UK: /kruːˈseɪdə^r/

WordReference Random House Learner's Dictionary of American English © 2025

cru•sade /kruˈseɪd/   n., v., -sad•ed, -sad•ing. 
n. [countable]

1. World History [often: Crusade] any of the military campaigns or wars undertaken by the Christians of Europe in the 11th, 12th, and 13th centuries to recapture the Holy Land from the Muslims.
2. a strong movement, campaign, or activity on behalf of a cause:
   a literacy crusade.

v. [no object]

3. to go on or take part in a crusade:
   She was crusading for more aid to the unemployed.

cru•sad•er, n. [countable]

WordReference Random House Unabridged Dictionary of American English © 2025

cru•sade  (kro̅o̅ sād′), n., v., -sad•ed, -sad•ing. 
n. 

1. World History (often cap.) any of the military expeditions undertaken by the Christians of Europe in the 11th, 12th, and 13th centuries for the recovery of the Holy Land from the Muslims.
2. World History any war carried on under papal sanction.
3. any vigorous, aggressive movement for the defense or advancement of an idea, cause, etc.:
   a crusade against child abuse.

v.i. 

4. to go on or engage in a crusade.

• Middle French. See cross, -ade¹
• Spanish cruzada; replacing croisade
• earlier crusada 1570–80

cru•sad′er, n.