Postponement indeed on the way (4)
I believe the answer is:
stay
'postponement' is the definition.
(as in a stay of execution)
'indeed on the way' is the wordplay.
'indeed' becomes 'ay' ('ay' and 'aye' can mean yes).
'on' says to put letters next to each other.
'the way' becomes 'st' (abbreviation for street).
'ay' put after 'st' is 'STAY'.
(Other definitions for stay that I've seen before include "Postpone" , "Remain; suspend" , "Stick around" , "Remain; prop" , "Delay (execution)" .)