cow (n.)

Old English cu "cow," from Proto-Germanic *kwon (source also of Old Frisian ku, Middle Dutch coe, Dutch koe, Old High German kuo, German Kuh, Old Norse kyr, Danish, Swedish ko), earlier *kwom, from PIE root *gwou- "ox, bull, cow."

cow (v.)

"intimidate," c. 1600, probably from Old Norse kuga "oppress," which is of unknown origin, but perhaps having something to do with cow (n.) on the notion of easily herded. Related: Cowed; cowing.