Moving or able to move quickly; happening in a short time. As a verb, it also means to go without food for a period of time, especially for religious or health reasons.
The “quick” sense comes from Old English “fæst” meaning “firm, fixed,” which developed into “firmly, strongly” and then “quickly.” The “not eating” sense comes from Old English “fæstan” meaning “to observe abstinence,” possibly related but with a different development.
Try Another Word