Irritability (3,6)
There are a few possibilities for this:
ill temper
'irritability' is the definition.
(synonyms)
This is all the clue.
(Other definitions for petulance that I've seen before include "Bad temper, sulkiness" , "ill humour" , "Peevishness" , "Childish sulkiness" , "Peevish irritation" .)
'irritability' is the definition.
(I know that testiness is a type of irritability)
This is the entire clue.
(Other definitions for testiness that I've seen before include "Irascibility" , "Irritability" .)
'irritability' is the definition.
(synonyms)
This is all the clue.
(Other definitions for surliness that I've seen before include "Biliousness, irritability" , "unfriendly state" , "Sullen churlishness" .)
'irritability' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for ill temper that I've seen before include "Irritability" , "Surliness" , "black humour" .)