Expression of annoyance when the scores are levelled (5)
I believe the answer is:
deuce
This clue is a double definition.
'expression of annoyance' is the first definition.
'when the scores are levelled' is the second definition.
(a score of 40-40 in tennis)
(Other definitions for deuce that I've seen before include "Two in cards - score in tennis" , "Forty-all in tennis" , "Level of tennis" , "situation of no advantage to either side" , "A two in playing cards" .)