Reticent about trees (5)
I believe the answer is:
terse
'reticent' is the definition.
Both the answer and definition are adjectives. Maybe you can see an association between them that I can't see?
'about trees' is the wordplay.
'about' indicates an anagram.
'trees' anagrammed gives 'TERSE'.
Can you help me to learn more?
(Other definitions for terse that I've seen before include "Sparing with words; abrupt" , "Curt, concise" , "Brusque and curt" , "Sententious" , "Reset to be pithy" .)