prefix usually meaning "away, opposite, completely," from Old English for-, indicating loss or destruction, but in other cases completion, and used as well with intensive or pejorative force, from Proto-Germanic *fur "before, in" (source also of Old Norse for-, Swedish för-, Dutch ver-, Old High German fir-, German ver-); from PIE *pr-, from root *per- (1) "forward," hence "in front of, before, toward, near, against."
In verbs the prefix denotes (a) intensive or completive action or process, or (b) action that miscarries, turns out for the worse, results in failure, or produces adverse or opposite results. In many verbs the prefix exhibits both meanings, and the verbs frequently have secondary and figurative meanings or are synonymous with the simplex. [Middle English Compendium]
Probably originally in Germanic with a sense of "forward, forth," but it spun out complex sense developments in the historical languages. Disused as a word-forming element in Modern English. Ultimately from the same root as fore (adv.). From its use in participles it came to be an intensive prefix of adjectives in Middle English (for example Chaucer's forblak "exceedingly black"), but all these now seem to be obsolete.
word-forming element meaning "wax, waxy," from Latinized form of Greek kēros "beeswax," a word of unknown origin with no obvious ulterior connections. "As there is no evidence for Indo-European apiculture, we have to reckon with foreign origin for κηρός" [Beekes].
word-forming element meaning "pressure," from Greek piezein "to press tight, squeeze," from PIE *pisedyo- "to sit upon" (source also of Sanskrit pidayati "presses, oppresses"), from *pi "on," short for *epi (see epi-) + root *sed- (1) "to sit." First in piezometer (1820), an instrument for ascertaining or testing pressure. It was in common use in word formation from c. 1900.
word-forming element meaning "around, round about, all around, on all sides," from Latin adverb and preposition circum "around, round about," literally "in a circle," probably accusative form of circus "ring" (see circus). The Latin word was commonly used in word-formation. In French, the element became circon-; Kitchin points out that con for cum is common even in classical Latin. For sense development, compare German rings "around."