goat

Goat comes from Middle English goot (also spelled got or gat), from Old English gāt, from Proto-West Germanic *gait, from Proto-Germanic *gaits, which itself was borrowed from an unknown substrate language.

The animal's name stayed remarkably stable across centuries of Germanic languages, but English later attached a new, unflattering sense to it: 'lecherous man,' born from the slang expression 'horny as a goat.'

The facts point only to its Germanic ancestors, *gait and *gaits, rather than to any sibling word still used in English today.