secreting organ of the body, Old English lifer, from Proto-Germanic *librn (cognates: Old Norse lifr, Old Frisian livere, Middle Dutch levere, Dutch lever, Old High German lebara, German Leber "liver"), perhaps from PIE *leip- "to stick adhere; fat." Formerly believed to be the body's blood-producing organ; in medieval times it rivaled the heart as the supposed seat of love and passion, hence lily-livered. Liver-spots, once thought to be caused by a dysfunction of the organ, is attested from 1730.

"one who lives (in a particular way)," late 14c., agent noun from live, v..