Curt, abrupt (5)
I believe the answer is:
terse
I believe this clue is a double definition.
'curt' is the first definition.
(synonyms)
'abrupt' is the second definition.
(I've seen this before)
(Other definitions for terse that I've seen before include "Trees (anag.)" , "Crisp and brief" , "Briefly expressed" , "Aphoristic" , "Pithy among trees" .)