flounder (v.) Look up flounder at Dictionary.com
"struggle awkwardly and impotently," especially when hampered somehow, 1590s, of uncertain origin, perhaps an alteration of founder (q.v.), influenced by Dutch flodderen "to flop about," or native verbs in fl- expressing clumsy motion. Figurative use is from 1680s. Related: Floundered; floundering. As a noun, "act of struggling," by 1867.
flounder (n.) Look up flounder at Dictionary.com
"flatfish," c.1300, from Anglo-French floundre, Old North French flondre, from Old Norse flydhra, from Proto-Germanic *flunthrjo (cognates: Middle Low German vlundere, Danish flynder, Old Swedish flundra "flatfish"), suffixed and nasalized form of PIE *plat- "to spread" (cognate: Greek platys "flat, wide, broad;" see plaice).