struggle vs flounder

struggle and flounder both are nouns.

Word	Noun	Adjective	Verb	Adverb
struggle	Yes	No	Yes	No
flounder	Yes	No	Yes	No

As verbs, flounder is a hyponym of struggle; that is, flounder is a word with a more specific, narrower meaning than struggle:

Other hyponyms of struggle include drive, labor, labour, push, tug.

struggle (noun)	flounder (noun)
strenuous effort	any of various European and non-European marine flatfish
an energetic attempt to achieve something	flesh of any of various American and European flatfish
an open clash between two opposing groups (or individuals)

struggle (verb)	flounder (verb)
be engaged in a fight; carry on a fight	walk with great difficulty
to exert strenuous effort against opposition	behave awkwardly; have difficulties
climb awkwardly, as if by scrambling
make a strenuous or labored effort