Career knock will slow your progress down (5,4)

I believe the answer is:

speed bump

'will slow your progress down' is the definition.

'career knock' is the wordplay.
'career' becomes 'speed'.
'knock' becomes 'bump' ('bump' can be a synonym of 'knock').
'speed'+'bump'='SPEED BUMP'

(Other definitions for speed bump that I've seen before include "traffic checker" , "Sleepng policeman" , "Sleeping policeman" , "Traffic-calming measure (B, not H)" , "Traffic-calming device" .)

I've seen this clue in The Guardian.

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