Old barrier starts to get dented (7)
I believe the answer is:
damaged
'dented' is the definition.
(similar in meaning)
'old barrier starts' is the wordplay.
'old' becomes 'aged' (similar in meaning).
'barrier' becomes 'dam' (dam is a kind of barrier).
'starts' is a charade indicator (letters next to each other).
'aged' put after 'dam' is 'DAMAGED'.
'to get' is the link.
(Other definitions for damaged that I've seen before include "Flawed, harmed" , "Marred" , "Hurt" , "Harmed, injured or spoiled" , "Sullied or harmed" .)