The word 'vixen' originates from the Old English fyxen, itself a feminine form of fox. The initial 'f' sound shifted to 'v' in the southern Middle English dialect due to a common phonetic change. This southern form eventually became standard. The term's primary zoological meaning was extended metaphorically to describe a woman with a sharp temper or spiteful nature, drawing on cultural associations of the fox with cunning and a perceived ill-temper. This pejorative figurative sense has been in use since at least the 16th century.

The word is a simplex. It is a single, unsegmentable unit in modern English, derived from the Old English fyxen, meaning "female fox."