Question essentially put by unconfined picky brief (5)
I believe the answer is:
quick
'picky brief' is the definition.
'quick' can be an answer for 'brief' (thesaurus). I am not sure about the 'picky' bit.
'question essentially put by unconfined' is the wordplay.
'question' becomes 'q'.
'essentially' means to look at the middle letters.
'by unconfined' becomes 'ick' (I can't explain this - if you can you should give a lot more credence to this answer).
The centre of 'put' is 'u'.
'q'+'u'+'ick'='QUICK'
Can you help me to learn more?
(Other definitions for quick that I've seen before include "Speedy" , "living" , "Swift" , "Part of fingernail" , "Fast; alive" .)