Sort of a tree, one seen in refectory? (5)
I believe the answer is:
eater
'one seen in refectory?' is the definition.
(a refectory is a place to eat food)
'sort of a tree' is the wordplay.
'sort of' indicates an anagram.
'a'+'tree'='atree'
'atree' is an anagram of 'EATER'.
(Other definitions for eater that I've seen before include "Person taking course" , "One consuming" , "Consumer at table" , "Consumer of food" , "Type of apple" .)