Very wet turf on lair (6)
I believe the answer is:
sodden
'very wet' is the definition.
'turf on lair' is the wordplay.
'turf' becomes 'sod' (synonyms).
'on' is a charade indicator (letters next to each other).
'lair' becomes 'den' (synonyms).
'sod'+'den'='SODDEN'
(Other definitions for sodden that I've seen before include "Waterlogged" , "'Soaked, sopping (6)'" , "Soaking wet" , "Drenched through, really wet" , "Soaked to the skin" .)