When I write these entries, I try to keep them fairly minimal, but I thought I’d add a few details about this one here.
According to the Oxford English Dictionary, “coward” is a straightforward borrowing of Old French “couart” or “couard” and can be traced back to a word meaning “tail,” either in reference to a fearful animal tucking its tail between its legs or “turning tail.”
The OED also lists various uses of “coward” as an adjective, but these are all unusual in modern English, so I ignored them. The word has other specialized uses, including in heraldry, where it describes an image of an animal with its tail tucked between its legs.
“Cower” is listed with this etymological note:
perhaps of Norse derivation: compare Icelandic kúra to sleep, doze, Swedish kura , Danish kure , to squat; also modern German kauern to cower, of which the antecedents are unknown.
The entry for the verb “cower” also notes a rare transitive form meaning “to lower, bend down” (example: “Byron Don Juan: Canto III xxxii. 19 The patriarch of the flock all gently cowers His sober head”).
The verb “cow” is probably Nordic. The OED cites similar words in Old Norse, Norwegian, and Swedish. This seems to be the only one of the three to have been connected with the bovine species.
Then there are the few folks who refer to the playwright as “Noel Cowered.” Rare, but amusing.