Burglary falling apart, mostly (5-2)

I believe the answer is:

break-in

'burglary' is the definition.
(I've seen this before)

'falling apart mostly' is the wordplay.
'falling apart' becomes 'breaking' ('break' can be a synonym of 'fall apart').
'mostly' means to remove the last letter (most but not all of the word).
'breaking' with its last letter taken off is 'BREAK-IN'.

(Another definition for break-in that I've seen is " Criminal entry".)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.