crusader

Plural: crusaders

Noun

• One who campaigns vigorously for a cause or ideal.
• a disputant who advocates reform
• a warrior who engages in a holy war
  • "the Crusaders tried to recapture the Holy Land from the Muslims"
• A fighter or participant in the medieval Crusades.
• A person engaged in a crusade.
• An American, especially a soldier or leader who wages war against Islamist militants.
• A Westerner; a Christian, especially of European descent or a missionary.
• (either attributively or in the plural) The United States and its Western allies.

Examples

• He was a CRUSADER for playing only dictionary-approved words, never resorting to slang.

Synonyms

meliorist, reformer, reformist, social reformer