Extra delivery (2-4)
I believe the answer is:
no-ball
I believe this clue is a double definition.
'extra' is the first definition.
(cricket)
'delivery' is the second definition.
(I have seen 'Illegal delivery' mean 'no ball' so perhaps 'delivery' could also mean 'no ball')
(Other definitions for no-ball that I've seen before include "Extra, in cricket" , "Illegal delivery by bowler in cricket" .)