Painter valiantly covering gap (8)
I believe the answer is:
interval
'gap' is the definition.
(I've seen this in another clue)
'painter valiantly covering' is the wordplay.
'covering' indicates the answer is hidden within the clue.
'INTERVAL' can be found hidden inside 'painter valiantly'.
(Other definitions for interval that I've seen before include "breather" , "Break in activity" , "Time between two events" , "A break as in travel" , "Pause (between acts)" .)