In bar, tea's ordered for such a person, perhaps (9)
I believe the answer is:
abstainer
'such a person perhaps' is the definition.
I can't judge whether this definition defines the answer.
'in bar tea's ordered' is the wordplay.
'ordered' indicates anagramming the letters.
'in'+'bar'+'teas'='inbarteas'
'inbarteas' anagrammed gives 'ABSTAINER'.
'for' is the link.
Can you help me to learn more?
(Other definitions for abstainer that I've seen before include "Band of Hope member" , "One declining to vote" , "one who avoids the hard stuff" , "One choosing not to vote" , "one on the wagon" .)