Flook (noun) is a Scots and Northern English dialect term for flounder, a flatfish of the family Pleuronectidae. The word persists in historical fishing communities along the North Sea and Baltic coasts.
The term endures in coastal dialects of Scotland (Fife, Angus, Aberdeenshire) and Northeast England, reflecting the rich maritime vocabulary of communities historically dependent on small-scale fisheries. In standard English, "flounder" has replaced "flook," but the dialect word remains a marker of regional identity.
Note: "Flook" is unrelated to the Irish flute ensemble The Flook or the obsolete verb "to flook" (to flounder/struggle).