The most common and most likely answer to this crossword clue is the 7 letter word IMPLODE
I
M
P
L
O
D
E
More clues leading to the result IMPLODE
- Pop idol gains 1,000 pence by euro’s collapse
- Cave in Spain, base for one male tramp
- Politician appears in Oldie that’s reviewed collapse
- Collapse of rich source of wicked spirits?
- Almost suggest poem and go off
- Dim Pole disorientated in collapse
- Rogue party involved in the Spanish revolution's collapse
- Cave in the central part of Simla with dope is afire
- Mischief getting part of mine to collapse
- Rich source of malevolent spirits causing collapse?
Buddy explains!

The straight part
We know that "Collapse" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case collapse = implode.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does IMPLODE mean?
IMPLODE verb- To collapse or burst inward violently.
- To compress (data) with a particular algorithm.