The most common and most likely answer to this crossword clue is the 4 plus 5 letter word LAST STRAW
I've seen this crossword clue in The Guardian
L
A
S
T
S
T
R
A
W
More clues leading to the result LAST STRAW
- Ultimate difficulty for camel?
- No more suckers? That's intolerable
- Endures temperature — bitterly cold — at breaking point
- Concluding provocation upset stalwarts
- Tipping Point? It’s where shoes may be fashionable pale yellow colour
- Tons carried by girl, hideous lump to lift a back-breaker?
- Breaking point? Carries on returning growth
- A back-breaking weight
- Goes on and on about blemish that leads to blown fuse?
- Endures temperature, bitterly cold, but that’s the limit
Buddy explains!

The straight part
We know that "that leads to blown fuse?/that leads to blown fuse?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case that leads to blown fuse?/that leads to blown fuse? = last straw.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.