Being in poor condition, the old mare showed her years (7)
I believe the answer is:
damaged
'being in poor condition' is the definition.
(I've seen this before)
'old mare showed her years' is the wordplay.
I cannot quite see how this works, but
'old' could be 'aged' (similar in meaning) and 'aged' is present in the answer.
The remaining letters 'dam' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
'the' is the link.
Can you help me to learn more?
(Other definitions for damaged that I've seen before include "Impaired" , "Flawed, harmed" , "Sullied or harmed" , "Harmed, injured or spoiled" , "Marred" .)