Staff about to get more promising (7)
I believe the answer is:
crosier
'staff' is the definition.
(I know that crosier is a type of staff)
'about to get more promising' is the wordplay.
'about' becomes 'c' (abbreviation for 'circa').
'to get' says to put letters next to each other.
'more promising' becomes 'rosier' ('rosy' can be a synonym of 'promising').
'c'+'rosier'='CROSIER'
(Other definitions for crosier that I've seen before include "Bishop's crook" , "A bishop's staff as symbol of office" , "one's hooked!" , "Ecclesiastical staff" , "Staff carried by a bishop" .)