Pale second (4)
I believe the answer is:
post
I believe this clue is a double definition.
'pale' is the first definition.
(I've seen this in other clues)
'second' is the second definition.
(as in posted or seconded to a job)
(Other definitions for post that I've seen before include "ob" , "Spot the mail" , "delivery" , "Maybe letters" , "Stake, job or mail" .)