Old woman on run gets hurt (3)
I believe the answer is:
'hurt' is the definition.
(both can mean to harm)
'old woman on run' is the wordplay.
'old woman' becomes 'ma' (both can mean someone's mother).
'on' means one lot of letters go next to another.
'run' becomes 'r' (cricket abbreviation).
'gets' is the link.
(Other definitions for mar that I've seen before include "Make imperfect" , "A windy month" , "when spring growth starts?" , "Spanish main?" , "Spoil stuff" .)