Quartermaster seems somewhat curt (5)
I believe the answer is:
terse
'curt' is the definition.
(I know that curt can be written as terse)
'quartermaster seems somewhat' is the wordplay.
'somewhat' says the answer is hidden in the clue.
'TERSE' is hidden within 'quartermaster seems'.
(Other definitions for terse that I've seen before include "Short and sharp" , "Abrupt, concise" , "Compact" , "Pithy and concise" , "Concise about trees" .)