pip-squeak vs small fry

pip-squeak and small fry both are nouns.

Word	Noun	Adjective	Verb	Adverb
pip-squeak	Yes	No	No	No
small fry	Yes	No	No	No

As nouns, pip-squeak and small fry are synonyms defined as:

Other synonyms of pip-squeak include squirt.

pip-squeak (noun)	small fry (noun)
someone who is small and insignificant	someone who is small and insignificant
	a young person of either sex