supporter (n.)

late 14c., supporten, "to hold up, prop up, bear the weight of;" also "to aid" someone, "speak in support or advocacy of;" also "put up with, bear without opposition, endure without being overcome, tolerate," from Old French suporter "to bear, endure, sustain, support" (14c.) and directly from Latin supportare "convey, carry, bring up, bring forward." This is from assimilated form of sub "up from under" (see sub-) + portare "to carry" (from PIE root *per- (2) "to lead, pass over").

It is attested by early 15c. as "supply funds or means for," especially "supply with the necessities of life." Of abstract things (a course of action, etc.) by 1630s. In reference to motions, propositions, etc., by 1736. In military use, of troops in battle, by 1848. In theater, originally "act (the part), represent on stage" (1709); by 1889 as "accompany or act second to a leading performer." The sense of "be a fan of" a sports team is by 1952. Related: Supported; supporting.