castaway n.

c. 1200, "throw, throw violently, fling, hurl," from a Scandinavian source akin to Old Norse kasta "to throw" (cognate with Swedish kasta, Danish kaste, North Frisian kastin), a word of uncertain origin.

The meaning "to form in a mold" is late 15c. In the sense of "to throw" it replaced Old English weorpan (see warp (v.)), and itself largely has been superseded by throw, though cast still is used of fishing lines (17c.) and glances (13c.).

From c. 1300 as "emit, give out;" also "throw to the ground;" also "shed or throw off;" also "calculate, find by reckoning; chart (a course)." From late 14c. as "to calculate astrologically." From late 15c. as "bring forth abortively or prematurely." From 1711 as "distribute the parts (of a play) among the actors." Of votes, from 1840, American English. To cast up is from 1530s as "compute, reckon" (accounts, etc.), late 15c. as "eject, vomit."

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.