Brief encountered in quarter sessions (5)
I believe the answer is:
terse
'brief' is the definition.
(synonyms)
'encountered in quarter sessions' is the wordplay.
'encountered in' indicates the answer is hidden within the clue.
'TERSE' is hidden within 'quarter sessions'.
(Other definitions for terse that I've seen before include "Short and sharp" , "Pithy and concise" , "Curt, laconic of speech" , "Curtly brief" , "Short and to the point" .)