Master moves tree in vehicle (7)
I believe the answer is:
veteran
'master' is the definition.
(thesaurus)
'moves tree in vehicle' is the wordplay.
'moves' indicates an anagram.
'in' means one lot of letters goes inside another.
'vehicle' becomes 'van' (type of vehicle).
'tree' is an anagram of 'eter'.
'eter' placed within 'van' is 'VETERAN'.
(Other definitions for veteran that I've seen before include "Long-serving" , "Old serving man" , "Describing cars built before 1919, especially before 1905" , "he's seen a lot of service" , "Old hand, ex-service person" .)