Clog with time for vandalism (8)
I believe the answer is:
sabotage
'for vandalism' is the definition.
(I've seen this before)
'clog with time' is the wordplay.
'clog' becomes 'sabot' (both can mean a type of shoe).
'with' means one lot of letters go next to another.
'time' becomes 'age' (an age is a period of time).
'sabot'+'age'='SABOTAGE'
(Other definitions for sabotage that I've seen before include "Subvert" , "enemy action" , "cripple" , "Scupper" , "malicious damage" .)