Know how to use "fewer" and "less"? Find out.
prefix usually meaning "away, opposite, completely," from Old English for-, indicating loss or destruction, or completion, also used as an intensive or pejorative element, which is related to Old Norse for-, Dutch ver-, Old High German fir-, German ver-; from PIE *pr-, from root *per- (1) "forward, through" (see per). Probably originally in Germanic with a sense of "forward, forth," but with complex sense developments in the various languages. Ultimately from the same root as fore (adv.).