1960–65,Americanism; probably for GI shits; see GI, -s3
[ jee-ahy ]
/ ˈdʒiˈaɪ /
noun,pluralGI's or GIs.
a member or former member of the U.S. armed forces, especially an enlisted soldier.
rigidly adhering to military regulations and practices; regimented; spit-and-polish: a platoon leader who tried to be more GI than anyone else.
of a standardized style or type issued by the U.S. armed forces: GI shoes; GI blankets.
conforming to the regulations or practices of the U.S. armed forces: Every recruit must get a GI haircut.
of, relating to, or characteristic of a U.S. enlisted person: a typical peacetime GI complaint.
verb (used with object),GI'd,GI'ing.
to clean in preparation for inspection: to GI the barracks.
verb (used without object),GI'd,GI'ing.
to follow military regulations and customs closely; shape up: You'd better learn to GI if you want to be promoted.
Origin of GI
1915–20; orig. abbreviation of galvanized iron, used in U.S. Army bookkeeping in entering articles (e.g., trash cans) made of it; later extended to all articles issued (as an assumed abbreviation of government issue) and finally to soldiers themselves
also GI, 1936 as an adjective meaning "U.S. Army equipment," American English, apparently an abbreviation of Government Issue, and applied to anything associated with servicemen. Transferred sense of "U.S. Army soldier" arose during World War II (first recorded 1943), apparently from the jocular notion that the men themselves were manufactured by the government.
An earlier G.I. (1908) was an abbreviation of galvanized iron, especially in G.I. can, a type of metal trash can; the term was picked up by U.S. soldiers in World War I as slang for a similar-looking type of German artillery shells. But it is highly unlikely that this G.I. came to mean "soldier." No two sources seem to agree on the entire etymology, but none backs the widespread notion that it stands for *General Infantry. GI Joe "any U.S. soldier" attested from 1942 (date in OED is a typo).