Ten years associated with heartless nest, corrupt (8)
I believe the answer is:
decadent
'corrupt' is the definition.
(thesaurus)
'ten years associated with heartless nest' is the wordplay.
'ten years' becomes 'decade' (I've seen this before).
'associated with' means one lot of letters go next to another.
'heartless' suggests removing the centre.
'nest' with its middle taken out is 'nt'.
'decade'+'nt'='DECADENT'
(Other definitions for decadent that I've seen before include "Reflecting cultural decline" , "base?" , "abandoned" , "Decanted in corrupt way" , "Lacking in moral vigour" .)