Beat former limit (9)
I believe the answer is:
threshold
'limit' is the definition.
(synonyms)
'beat former' is the wordplay.
'beat' becomes 'thresh' (threshing is a kind of beating).
'former' becomes 'old' (both can mean previous).
'thresh'+'old'='THRESHOLD'
(Other definitions for threshold that I've seen before include "Verge" , "Doorstep" , "The bride may be carried across this door bottom" , "Beginning" , "Doorway, entrance" .)