What covers painting? Dirt (5)
I believe the answer is:
earth
'dirt' is the definition.
(I've seen this before)
'what covers painting?' is the wordplay.
'what' becomes 'eh' (sound used to ask 'what?' or 'pardon?').
'covers' indicates putting letters inside.
'painting?' becomes 'art' (painting is an art).
'eh' going around 'art' is 'EARTH'.
(Other definitions for earth that I've seen before include "Meek's inheritance" , "Heart of clay" , "underground shelter" , "our home" , "Fox's burrow" .)