The most common and most likely answer to this crossword clue is the 8 letter word SNAPPIER
I've seen this crossword clue in The Daily Telegraph
S
N
A
P
P
I
E
R
More clues leading to the result SNAPPIER
Buddy explains!
The straight part
We know that "More irritable" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case more irritable = snappier.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 SNAPPIER mean?
SNAPPIER adjective- Rapid and without delay.
- Irritable.
- Tidy; well-dressed; sharp.
- Chilly, brisk, sharp.