The verb 'whet' originates from the Proto-Germanic root \hwatjaną, meaning "to sharpen" or "to incite." This root is connected to the Proto-Indo-European \kʷed-, "to sharpen," which also gives rise to words like 'quickness' through the sense of sharpness implying a keen, acute state. In Old English, hwettan was used literally for sharpening tools and weapons, a meaning that persists today. The figurative sense of stimulating the mind or appetite developed naturally from the concept of making something keen or acute, completing the word's journey from a physical action to an abstract metaphor.

The word is a simplex form derived from Old English hwettan, meaning "to sharpen." It is a Germanic root related to Old Norse hvetja and German wetzen.