nipper vs small fry

nipper and small fry both are nouns.

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

As nouns, nipper and small fry are synonyms defined as:

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

nipper (noun)	small fry (noun)
a grasping structure on the limb of a crustacean or other arthropods	someone who is small and insignificant
a young person of either sex	a young person of either sex