libertine UK /ˈlɪb.ə.tiːn/US /ˈlɪb.ɚ.tin/noun 3adjective 1forms 3 noun3 •(disapproving) Someone (especially a man) who takes no notice of moral laws, especially those involving sexual propriety; someone loose in morals; a pleasure-seeker.So the truth of the matter is that a libertine in love, if indeed a libertine can be in love, becomes from that moment in less of a hurry to enjoy the pleasures of the flesh. — 2007 •One who is freethinking in religious matters. •(historical) Someone freed from slavery in Ancient Rome; a freedman. adjective1 •Dissolute, licentious, profligate; loose in morals. formslibertines · more libertine · most libertine