Young man brewing green tea (8)
I believe the answer is:
teenager
'young man' is the definition.
(thesaurus)
'brewing green tea' is the wordplay.
'brewing' is an anagram indicator.
'green'+'tea'='greentea'
'greentea' anagrammed gives 'TEENAGER'.
(Other definitions for teenager that I've seen before include "14, perhaps" , "one that's not yet made a score?" , "Youngster" , "one with an unpredictable nature" , "Adolescent" .)