High-ranking officer damages Henry (7)
I believe the answer is:
marshal
'high-ranking officer' is the definition.
(I've seen this before)
'damages henry' is the wordplay.
'damages' becomes 'mars' (marring is a kind of damaging).
'henry' becomes 'hal'.
'mars'+'hal'='MARSHAL'
(Other definitions for marshal that I've seen before include "Maybe a bulldog" , "Arrange; senior officer" , "star part in a Western" , "Top officer" , "guide" .)