Dull part of cricket pitch (8)
I believe the answer is:
overcast
'dull' is the definition.
(as in dull weather)
'part of cricket pitch' is the wordplay.
'part of cricket' becomes 'over' (sequence of six balls bowled in cricket).
'pitch' becomes 'cast' (I've seen this in another clue).
'over'+'cast'='OVERCAST'
(Other definitions for overcast that I've seen before include "Of sky, covered with cloud" , "The sky covered by dark clouds" , "Cloud-covered" , "State of the sky when it is covered by clouds" , "(Of sky) cloudy, dull" .)