The most common and most likely answer to this crossword clue is the 2 plus 9 letter word GO BALLISTIC
I've seen this crossword clue in The Guardian
G
O
B
A
L
L
I
S
T
I
C
More clues leading to the result GO BALLISTIC
- Trap the lot with one’s sudden movement — then lose it
- Big cat so ill following mistreatment – become very angry
- Lose temper, mouth twitching, after everything starts to implode suddenly
- Pep pill taken by one before endless criticism makes one become violently angry
- Blow up many after a large programme in desert
Buddy explains!
The straight part
We know that "Lose temper/Lose temper" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case lose temper/lose temper = go ballistic.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.