Fool circling bear, briefly, and wild horse (7)
I believe the answer is:
mustang
'wild horse' is the definition.
(I've seen this before)
'fool circling bear briefly and' is the wordplay.
'fool' becomes 'mug' (synonyms).
'circling' means one lot of letters goes inside another (circling can mean going around or containing).
'bear briefly' becomes 'sta' (I can't explain this - if you can you should believe this answer much more).
'and' becomes 'n' (common abbreviation for 'and').
'sta'+'n'='stan'
'mug' enclosing 'stan' is 'MUSTANG'.
Can you help me to learn more?
(Other definitions for mustang that I've seen before include "Wild horse of the West" , "SW US wild horse" , "Small feral horse of the US" , "one running wild" , "Feral American horse" .)