What it means
To come clean is to finally stop ducking, tell the truth, and admit what you've been hiding. You use it when someone quits the excuses and lays it out properly, whether it's a big mess-up or some smaller daft secret. There's usually a bit of pressure in it too, like the lie's running out of road anyway.
Usage examples
"Mate, before you hear it from Dave, I’m coming clean, I clipped the wing mirror parking and legged it. I’ll sort it."
"He finally came clean about where he had really been all weekend."
"Just come clean with her, she will respect the honesty more than the excuse."
"Alright, I'm coming clean, I told Mum I was at Jake's but we were actually out till two."
"You may as well come clean now, the group chat receipts are already doing laps."
Where it comes from
This one is recorded in English from the early 20th century. Here, clean carries the sense of honest, clear, and free from anything shady. So if you come clean, you stop covering it up and tell it straight. The image is about clearing off the dirt and standing there with nothing hidden.
Other ways to say it
Editors of this term
Earthy Spark Tamer Official watcher of this expression
Tell me, what have you got for me?