Crash out Definition 1 of 3Pro Tip 1/3Physical Exhaustion Emphasizes the speaker's high level of tiredness when they decide to sleep. Walking all day, I could crash out anywhere. Pro Tip 2/3Suddenness Indicates that the sleep is often unexpected and happens suddenly. He crashed out mid-conversation, utterly drained. Pro Tip 3/3Casual Context Commonly used in informal settings among friends and family. After the party, we all crashed out in the living room.