flower child vs crusader

flower child and crusader both are nouns.

Word	Noun	Adjective	Verb	Adverb
flower child	Yes	No	No	No
crusader	Yes	No	No	No

As nouns, crusader is a hypernym of flower child; that is, crusader is a word with a broader meaning than flower child:

flower child: someone who rejects the established culture; advocates extreme liberalism in politics and lifestyle
crusader: a disputant who advocates reform

Other hypernyms of flower child include meliorist, reformer, reformist, social reformer.

flower child (noun)	crusader (noun)
someone who rejects the established culture; advocates extreme liberalism in politics and lifestyle	a disputant who advocates reform