The most common and most likely answer to this crossword clue is the 7 letter word IRACUND
I
R
A
C
U
N
D
More clues leading to the result IRACUND
Buddy explains!

The straight part
We know that "losing it" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case losing it = iracund.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 IRACUND mean?
IRACUND adjective- Angry; irritable