Future time in firm reviewed (5)
I believe the answer is:
later
'future' is the definition.
(synonyms)
'time in firm reviewed' is the wordplay.
'time' becomes 'ret' (I've seen this in other clues).
'in firm' becomes 'al' (I can't explain this - if you can you should believe this answer much more).
'reviewed' says the letters should be written backwards.
'ret'+'al'='retal'
'retal' backwards is 'LATER'.
Can you help me to learn more?
(Other definitions for later that I've seen before include "there's more behind" , "Alter (anag.)" , "Tomorrow (or next week)?" , "at a future date" , "Alert (anag.)" .)