Left to dry out in the den (4)
I believe the answer is:
lair
'the den' is the definition.
(synonyms)
'left to dry out' is the wordplay.
'left' becomes 'l' (common abbreviation).
'to dry out' becomes 'air' (airing is a kind of drying out).
'l'+'air'='LAIR'
'in' is the link.
(Other definitions for lair that I've seen before include "animal refuge" , "Habitat of a wild animal" , "Wild animal's place of refuge" , "enclosure" , "Hiding place, den" .)