Come Unstuck Meaning
(idiomatic, Britain) To get into trouble, to have an accident or mishap, to go off the rails.
Example: 1960, P. G. Wodehouse, Jeeves in the Offing, chapter XII:
â€œWell, if you must know,â€ he said, â€œshe's broken the engagement.â€ This didn't get us any farther. We had assumed as much. You don't go calling people rats if love still lingers. â€œBut it's only an hour or so,â€ I said, â€œsince I left her outside a hostelry called the â€˜Fox and Gooseâ€™, and she had just been giving you a rave notice. What came unstuck? What did you do to the girl?â€