Balance table with rowers (13)
I believe the answer is:
counterweight
'balance' is the definition.
(synonyms)
'table with rowers' is the wordplay.
'table' becomes 'counter' (counter is a kind of table).
'with' becomes 'w' (short for with).
'rowers' becomes 'eight' (eight can mean a crew of eight rowers).
'counter'+'w'+'eight'='COUNTERWEIGHT'
(Other definitions for counterweight that I've seen before include "steadying force" , "The balance" , "Compensating mass" .)