Island opposed to firearms briefly gets support of America (7)
I believe the answer is:
antigua
'island' is the definition.
(I've seen this before)
'opposed to firearms briefly gets support of america' is the wordplay.
I cannot really understand how this works, but
'opposed' could be 'anti' (similar in meaning) and 'anti' is found in the answer.
'america' could be 'a' (common abbreviation - e.g. in organisation names) and 'a' is located in the answer.
The remaining letters 'gu' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for antigua that I've seen before include "Caribbean island linked with Barbuda" , "West Indies island" , "One of the Leeward Islands" , "warm island" , "Aga unit in the West Indies" .)