Teas brewed behind (4)
I believe the answer is:
seat
'behind' is the definition.
(synonyms)
'teas brewed' is the wordplay.
'brewed' indicates anagramming the letters.
'teas' is an anagram of 'SEAT'.
(Other definitions for seat that I've seen before include "MP's place in parliament" , "Take one and sit" , "Behind" , "MP's constituency" , "Somewhere to sit" .)