1960–65,Americanism; probably for GI shits; see GI, -s3
GI
or G.I.
[jee-ahy]
noun,pluralGI's or GIs.
a member or former member of the U.S. armed forces, especially an enlisted soldier.
adjective
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
