The word coward was taken sometime in the mid-1200s from Anglo-French couard, which comes from the Old French word coart or cuard, still with the same definition. The root of this is coe, meaning "tail" (from the Proto-Indo-European word for "tuft", kehw, through Latin cauda), and it's modified by the suffix -ard, which pejoratively denoted a person carrying out an action (and somehow traces to Proto-Indo-European kar, "hard". The notion is that a coward shows his or her tail when they flee. Now, it seems intuitive that coward would be related to the word cower, since both have to do with a person being afraid of things and they have a similar spelling. This, however, is surprisingly untrue. Cower comes, by way of Middle English curen, from Middle Low German kuren (which meant "lie in wait") or one of its cognates. This has no connection to the Italic word, which I find endlessly amusing.
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.