poster child vs shaver

poster child and shaver both are nouns.

Word	Noun	Adjective	Verb	Adverb
poster child	Yes	No	No	No
shaver	Yes	No	No	No

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

poster child: a child afflicted by some disease or deformity whose picture is used on posters to raise money for charitable purposes
shaver: a young person of either sex

Other hypernyms of poster child include child, fry, kid, minor, nestling, nipper, small fry, tiddler, tike, tyke, youngster.

poster child (noun)	shaver (noun)
a child afflicted by some disease or deformity whose picture is used on posters to raise money for charitable purposes	a razor powered by an electric motor
	a young person of either sex
	an adult male who shaves