Teenager thrilled, I hear, by beer drinking party (10)
I believe the answer is:
adolescent
'teenager' is the definition.
(synonyms)
'hear by beer drinking party' is the wordplay.
'hear' becomes 'scent' (I can't justify this - if you can you should give a lot more credence to this answer).
'by' says to put letters next to each other.
'beer' becomes 'ale' (type of beer).
'drinking' means one lot of letters goes inside another (inserted letters are consumed or drunk).
'party' becomes 'do' (do is a kind of party).
'ale' enclosing 'do' is 'adole'.
'scent' put after 'adole' is 'ADOLESCENT'.
'thrilled i' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for adolescent that I've seen before include "Immature" , "Teenager" , "Person in child-adult transition" , "sixth-former, say" , "At the stage between childhood and maturity" .)