Suffer junior to work (7)
I believe the answer is:
undergo
'suffer' is the definition.
(undergoing is a kind of suffering)
'junior to work' is the wordplay.
'junior' becomes 'under' (I've seen this in other clues).
'to work' becomes 'go' (synonyms).
'under'+'go'='UNDERGO'
(Other definitions for undergo that I've seen before include "Suffer, endure" , "Stand" , "experience needed" , "Suffer reverse" , "Endure or be subjected to" .)