late 14c., from M.L. infamosus, from L. in- "not" + famosus "celebrated." Meaning infl. by L. infamis "of ill fame," from in- "not, without" + fama "reputation." As a legal term, "disqualified from certain rights of citizens in consequence of conviction of a crime" (late 14c.). Infamy is late 15c., from O.Fr. infamie, from L. infamia.