Hit the hay/sack Definition 1 of 1Pro Tip 1/3Informal Speech Use 'hit the hay/sack' in casual conversations, not in formal or professional settings. I'm exhausted; I'm gonna hit the hay early tonight. Pro Tip 2/3Figurative Meaning 'Hit the hay/sack' means going to sleep but doesn't involve actual hitting. We've got an early start tomorrow, so let's hit the sack. Pro Tip 3/3Conversational Clue This phrase often implies that the speaker is tired or that it's the end of the day. We finished painting the house; time to hit the hay.