wonder child vs child

wonder child and child both are nouns.

Word	Noun	Adjective	Verb	Adverb
wonder child	Yes	No	No	No
child	Yes	No	No	No

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

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

wonder child (noun)	child (noun)
a prodigy whose talents are recognized at an early age	a young person of either sex
	a human offspring (son or daughter) of any age
	an immature childish person
	a member of a clan or tribe