Out Like a Light' is an expression used to describe someone falling ASLEEP very quickly. The crossword solutions for this term are UNCONSCIOUS, ASLEEP, FASTASLEEP, and SOUNDASLEEP. UNCONSCIOUS refers to a state in which a person is not aware of their surroundings or able to respond to stimuli. ASLEEP means that a person is sleeping and not awake. FASTASLEEP implies that the person fell ASLEEP very quickly. SOUNDASLEEP means that the person is sleeping deeply and soundly.