Hours revised taking in new career (6)
I believe the answer is:
onrush
'career' is the definition.
(I've seen this before)
'hours revised taking in new' is the wordplay.
'revised' indicates anagramming the letters.
'taking in' indicates putting letters inside.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'hours' anagrammed gives 'orush'.
'orush' going around 'n' is 'ONRUSH'.
(Other definitions for onrush that I've seen before include "sudden swoop" , "Forward charge of Hurons" , "Forceful forward flow" , "Career" , "Attack" .)