lie down intransitive verb 1.archaic: to go to bed for the night 2.: to lie on a bed for a brief rest : take a nap 3.obsolete: lie in 4.: to submit meekly or abjectly to defeat, disappointment, or insult < they will not take this violation of their rights lying down > 5.: to fail to perform or to neglect one's part deliberately < lie down on the job >