Foul place to clear (6)
I believe the answer is:
putrid
'foul' is the definition.
(I've seen this before)
'place to clear' is the wordplay.
'place' becomes 'put' ('put' can be a synonym of 'place'**).
'to clear' becomes 'rid' ('rid' can be a synonym of 'clear').
'put'+'rid'='PUTRID'
(Other definitions for putrid that I've seen before include "Really rotten and foul-smelling" , "Decaying, really rotten" , "Decaying, rotting" , "Bad smelling, rotting" , "contaminated" .)