fosterling vs small fry

fosterling and small fry both are nouns.

Word	Noun	Adjective	Verb	Adverb
fosterling	Yes	No	No	No
small fry	Yes	No	No	No

As nouns, small fry is a hypernym of fosterling; that is, small fry is a word with a broader meaning than fosterling:

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

fosterling (noun)	small fry (noun)
a child who is raised by foster parents	someone who is small and insignificant
	a young person of either sex