Mortified drone showed sign of injury (7)
I believe the answer is:
humbled
'mortified' is the definition.
('humble' can be a synonym of 'mortify')
'drone showed sign of injury' is the wordplay.
'drone' becomes 'hum' (drone can mean to make a humming sound).
'showed sign of injury' becomes 'bled'.
'hum'+'bled'='HUMBLED'
(Other definitions for humbled that I've seen before include "Brought low" , "Crushed" .)