throwaway adj.

"to project, propel," c. 1300, from Old English þrawan "to twist, turn, writhe, curl," (past tense þreow, past participle þrawen), from Proto-Germanic *threw- (source also of Old Saxon thraian, Middle Dutch dræyen, Dutch draaien, Old High German draen, German drehen "to turn, twist;" not found in Scandinavian or Gothic), from PIE root *tere- (1) "to rub, turn," with derivatives referring to twisting.

Not the usual Old English word for "to throw" (weorpan, related to warp (v.) was common in this sense). The sense evolution may be via the notion of whirling a missile before throwing it. The sense of "put by force" (as in throw in jail) is first recorded 1550s; that of "confuse, flabbergast" is from 1844; that of "lose deliberately" is from 1868. To throw a party was in U.S. college slang by 1916.

To throw the book at(someone) is 1932, from notion of judge sentencing a criminal from a law book full of possible punishments. To throw (one's) hat in the ring "issue a challenge," especially to announce one's candidacy, first recorded 1917. To throw up "vomit" is first recorded 1732. To throw (someone) off "confuse by a false scent" is from 1891.

Middle English awei, from late Old English aweg, earlier on weg "on from this (that) place;" see a- (1) + way (n.).

The meaning "from one's own or accustomed place" is from c. 1300; that of "from one state or condition to another" is from mid-14c.; that of "from one's possession (give away, throw away) is from c. 1400. Colloquial use for "without delay" (fire away, also right away) is from the earlier sense of "onward in time" (16c.). The meaning "at such a distance" (a mile away) is by 1712. Intensive use (as in away back) is American English, attested by 1818. Of sporting events played at the other team's field or court, by 1893.