Expert not befuddled right away (6)
I believe the answer is:
pronto
'right away' is the definition.
(I've seen this in another clue)
'expert not befuddled' is the wordplay.
'expert' becomes 'pro' (short for professional).
'befuddled' is an anagram indicator.
'not' is an anagram of 'nto'.
'pro'+'nto'='PRONTO'
(Other definitions for pronto that I've seen before include "Quickly (sl.)" , "Promptly, without delay" , "Quickly, promptly" , "Proton (anag.)" , "Quick as you can, amigo" .)