Alter design afterwards (5)
I believe the answer is:
later
'afterwards' is the definition.
(I know that afterwards can be written as later)
'alter design' is the wordplay.
'design' indicates anagramming the letters.
'alter' with letters rearranged gives 'LATER'.
(Other definitions for later that I've seen before include "Alter (anag.)" , "After a given point in time" , "Afterward, subsequent" , "At a time in the future" , "Tomorrow (or next week)?" .)