Spoil the sailor with a broken shin (7)
I believe the answer is:
tarnish
'spoil' is the definition.
(I've seen this before)
'sailor with a broken shin' is the wordplay.
'sailor' becomes 'tar' (tar can mean a sailor).
'with' means one lot of letters go next to another.
'a broken' indicates anagramming the letters.
'shin' is an anagram of 'nish'.
'tar'+'nish'='TARNISH'
'the' acts as a link.
(Other definitions for tarnish that I've seen before include "Stain or blemish, perhaps a reputation" , "spot" , "Besmirch" , "Go dull" , "Stain like silver" .)