Saturated turf by animal's lair (6)
I believe the answer is:
sodden
'saturated' is the definition.
('sodden' can be a synonym of 'saturated')
'turf by animal's lair' is the wordplay.
'turf' becomes 'sod' ('sod' can be a synonym of 'turf').
'by' means one lot of letters go next to another.
'animal's lair' becomes 'den' (I've seen this before).
'sod'+'den'='SODDEN'
(Other definitions for sodden that I've seen before include "Muddy" , "Totally saturated" , "Drenched through, really wet" , "Made very wet" , "Soaked to the skin" .)