Compliant, old criminal about to perish (8)
I believe the answer is:
obedient
'compliant' is the definition.
(similar in meaning)
'old criminal about to perish' is the wordplay.
'old' becomes 'o' (abbreviation).
'criminal' becomes 'bent' (bent can mean corrupt or criminal).
'about' is an insertion indicator.
'to perish' becomes 'die' ('die' can be a synonym of 'perish').
'bent' enclosing 'die' is 'bedient'.
'o'+'bedient'='OBEDIENT'
(Other definitions for obedient that I've seen before include "Deferential" , "Complying with orders" , "co-operative?" , "Willing to comply" , "A good dog should be" .)