1958, intransitive, "go away," chiefly British; the transitive meaning "annoy (someone)" is by 1968, chiefly U.S.; from piss (v.) + off (adv.). Pissed off "angry, fed up" is attested by 1946 (Partridge says 1937); said to have been used in the military in World War II; in common use from 1970s.

"escape," c. 1600, from get (v.) + off (adv.). Sexual sense attested by 1973.

1570s, of firearms, etc., "explode, be discharged;" see go (v.) + off (adv.); meaning "depart" is c. 1600; that of "deteriorate in condition" is from 1690s; that of "reprimand" is from 1941 (originally with at, since c. 2000 more often with on).

"retreat, stop annoying someone," by 1938, from the verbal phrase, from back (v.) + off (adv.).

"leave quickly," by 1956, perhaps from bugger off (see bugger (v.)), which chiefly is British (by 1920s) but was picked up in U.S. Air Force slang in the Korean War. Also see bug (v.3). To bug out "leave quickly, scram" is from 1953.

verbal phrase; see set (v.) + off (adv.). From 1590s as "make prominent by contrast," 1610s as "adorn." Intransitive sense of "start on or as on a journey" is from 1774. Meaning "separate from contect" (in typography) is from 1824; sense of "ignite, discharge, cause to explode" is from 1810.

"drive (something) away by violent blows," 1640s, from beat (v.) + off (adv.). The meaning "masturbate" is recorded by 1960s.

the legal doctrine of being bound by precedents, Latin, literally "to stand by things decided;" from stare "to stand" (from PIE root *sta- "to stand, make or be firm"). Second element from decidere "to decide, determine," literally "to cut off," from de- "off" (see de-) + caedere "to cut" (see -cide).

town in Scotland just across the border, proverbial from late 18c. as the customery place for English couples to run off and be married without parental consent.