1520s, "to unload, disburden," a literal sense now obsolete; 1570s as "relieve (of a charge, blame, etc.) resting on one; clear of something that lies upon the character as an imputation," from Latin exoneratus, past participle of exonerare "remove a burden, discharge, unload," from ex "out, out of, off" (see ex-) + onerare "to unload; overload, oppress," from onus (genitive oneris) "burden" (see onus). Related: Exonerated; exonerating.