Deface barrier, with time (6)
I believe the answer is:
damage
'deface' is the definition.
(thesaurus)
'barrier with time' is the wordplay.
'barrier' becomes 'dam' (dam is a kind of barrier).
'with' is a charade indicator (letters next to each other).
'time' becomes 'age' (age is a kind of time).
'dam'+'age'='DAMAGE'
(Other definitions for damage that I've seen before include "To vandalise" , "Harm; reparation" , "Mar" , "Impair and lower value" , "Deface, harm" .)