flounder

nouns

flesh of any of various American and European flatfish
is a type of (narrower)
sweet lean whitish flesh of any of numerous thin-bodied fish; usually served as thin fillets
any of various European and non-European marine flatfish
is a type of (narrower)
any of several families of fishes having flattened bodies that swim along the sea floor on one side of the body with both eyes on the upper side

verbs

walk with great difficulty
"He staggered along in the heavy snow"
behave awkwardly; have difficulties
"She is floundering in college"
is a type of (narrower)
make a strenuous or labored effort
"She struggled for years to survive without welfare"; "He fought for breath"