mid-15c., from guard (n.) or from Old French garder "to keep watch over, guard, protect, maintain, preserve" (corresponding to Old North French warder, see gu-), from Frankish *wardon, from Proto-Germanic *wardon "to guard" (from PIE root *wer- (3) "perceive, watch out for"). Italian guardare, Spanish guardar also are from Germanic. Related: Guarded; guarding.
1712, "belonging to a republic, of the nature of a republic, consonant to the principles of a republic," from republic + -an. With capital R-, "of, pertaining to, or favoring one of the various American parties that have been called Republican," by 1806 (the modern GOP dates from 1854). The French republican calendar was in use from Nov. 26, 1793 to Dec. 31, 1805. Earlier adjectives included republical (1650s), republicarian (1680s).
"one who favors a republican form of government or republican principles" (or, as Johnson puts it, "One who thinks a commonwealth without monarchy the best government"), 1690s; see republican (adj.).
With capital R-, in reference to a member of a specific U.S. political party (the Anti-Federalists) from 1782, though this was not the ancestor of the modern U.S. Republican Party, which dates from 1854. In between, National Republicans was a name of the party that opposed Jackson and rallied behind John Quincy Adams in late 1820s.
early 15c., "one who keeps watch, a body of soldiers," also "care, custody, guardianship," and the name of a part of a piece of armor, from French garde "guardian, warden, keeper; watching, keeping, custody," from Old French garder "to keep, maintain, preserve, protect" (see guard (v.)). Abstract or collective sense of "a keeping, a custody" (as in bodyguard) also is from early 15c. Sword-play and fisticuffs sense is from 1590s; hence to be on guard (1640s) or off (one's) guard (1680s). As a football position, from 1889. Guard-rail attested from 1860, originally on railroad tracks and running beside the rail on the outside; the guide-rail running between the rails.
also IRA, 1921, initialism (acronym) for Irish Republican Army, the full name of which attested from 1919.
ancient Semitic city of North Africa, rival of republican Rome, from Latin Carthago, from Phoenician quart khadash "new town." Related: Carthaginian.