Manservant with no time for depression (4)
I believe the answer is:
'depression' is the definition.
(vale is a kind of depression)
'manservant with no time' is the wordplay.
'manservant' becomes 'valet' (valet is a kind of manservant).
'with no' suggests deleting specific letters.
'time' becomes 't'.
'valet' with 't' taken away is 'VALE'.
'for' is the link.
(Other definitions for vale that I've seen before include "Glen; goodbye!" , "Long depression containing a river" , "Valley" , "Cheers" , "Trough between ridges" .)