1570-80; < Latinbelliger waging war (belli-, combining form of bellum war + ger-, base of gerere to conduct) + -ent; replacing belligerant < Latinbelligerant- (stem of belligerāns, present participle of belligerāre to wage war; see -ant)
1570s, from L. belligerantem (nom. belligerans), pp. of belligerare "to wage war," from bellum "war" + gerere "to bear, to carry." The noun meaning "party or nation at war" is from 1811. Related: Belligerence; belligerency.