"utter loudly, shout," also figurative, "make importunate demands or complaints," late 14c., from clamor (n.). Related: Clamored; clamoring.
"to cry out, speak with vehemence, make a loud outcry in words," 1560s, a back-formation from exclamation or else from French exclamer (16c.), from Latin exclamare "cry out loud, call out," from ex "out," perhaps here an intensive prefix (see ex-), + clamare "cry, shout, call" (from PIE root *kele- (2) "to shout"). Spelling influenced by claim. Related: Exclaimed; exclaiming.