Flier possibly hung up (3)
I believe the answer is:
bat
'up' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how they can define each other.
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for bat that I've seen before include "Nocturnal mouselike mammal" , "Night-flyer" , "Nocturnal flier" , "Pipistrelle" , "A mammal; a club" .)