Wet turf covers hole (6)
I believe the answer is:
sodden
'wet' is the definition.
('sodden' can be similar in meaning to 'wet')
'turf covers hole' is the wordplay.
'turf' becomes 'sod' ('sod' can be a synonym of 'turf').
'covers' means one lot of letters go next to another.
'hole' becomes 'den' (I've seen this in other clues).
'sod'+'den'='SODDEN'
(Other definitions for sodden that I've seen before include "Totally saturated" , "'Soaked, sopping (6)'" , "Soaking wet" , "Made very wet" , "Muddy" .)