Captain’s beginning injury appeal (5)
I believe the answer is:
charm
'appeal' is the definition.
('charm' can be a synonym of 'appeal')
'captain's beginning injury' is the wordplay.
'beginning' says to take the initial letters.
'injury' becomes 'harm' ('harm' can be a synonym of 'injury').
The first letter of 'captains' is 'c'.
'c'+'harm'='CHARM'
(Other definitions for charm that I've seen before include "Delightfulness" , "Attractive manner" , "pleasing feature" , "Make delighted" , "Beguile" .)