Move swiftly in profession (6)
I believe the answer is:
career
This clue is a double definition.
'move swiftly' is the first definition.
(career can mean to race around)
'profession' is the second definition.
(someone's profession is their career or occupation)
'in' acts as a link.
(Other definitions for career that I've seen before include "go very fast" , "Tear" , "One's professional life" , "charge" , "Progress in occupation" .)