Put a limit on again, getting tough (8)
I believe the answer is:
restrict
'put a limit on' is the definition.
(I've seen this before)
'again getting tough' is the wordplay.
'again' becomes 're' (prefix meaning 'again').
'getting' is a charade indicator (letters next to each other).
'tough' becomes 'strict' (I've seen this before).
're'+'strict'='RESTRICT'
(Other definitions for restrict that I've seen before include "Check" , "'Restrain, limit (8)'" , "Circumscribe" , "Limit, inhibit" , "Keep under control" .)