Jaunty officer, one spearing fish (7)
I believe the answer is:
lilting
'jaunty' is the definition.
Both the definition and answer are adjectives. Maybe there's a link between them I don't understand?
'officer one spearing fish' is the wordplay.
I cannot really understand how this works, but
'officer' could be 'lt' (abbreviation for lieutenant) and 'lt' is found within the answer.
'one' could be 'li' (I've seen this in other clues) and 'li' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for lilting that I've seen before include "With light rhythm, pleasant accent" , "Sing-song" .)