The time at night at which artificial lights are to be turned off, a curfew or bedtime. / The prescribed bedtime for persons living in a boarding school or staying in a hospital.

Alternative form of lights-out / Unconsciousness.

Third-person singular simple present indicative form of light out

(intransitive, slang, dated) To go away or depart, especially in haste or without notice.

present participle of light out

(idiomatic) To give someone a serious beating using one's fists; to punch someone until he or she is unconscious.

Synonym of punch someone's lights out

(idiomatic) To cause someone to become unconscious, especially by striking him or her.