The words "cower" and "coward" are etymologically unrelated, contrary to what I've been thinking for years. Coward was borrowed in the mid-1200s from the French word couard, and that's from Old French coart, with essentially the same definition as today. After eliminating the suffix -ard, denoting the possession of a quality, the root there is coe, meaning "tail" (because a coward runs away with their tail between their legs whenever they can). That's from Latin coda, an alteration of earlier cauda, which eventually derives from Proto-Indo-European kehw, still "tail". Cower, meanwhile, was taken in the mid-1300s from Middle German kuren, meaning "lie in wait" (with the modern connotation, it's waiting for your fears to pass). The etymology for that word is uncertain, but its possible Scandinavian heritage disprove any connection to coward.
Adam Aleksic, a rising sophomore studying linguistics and government at Harvard University, has been described as the internet's sixth most famous etymologist. He also has disturbing interests in politics, vexillology, geography, board games, conlanging, and law.