Throw up alcohol, originally in celebration (6)
I believe the answer is:
reveal
'throw' is the definition.
(thesaurus)
'up alcohol originally in celebration' is the wordplay.
'up alcohol originally' becomes 'a' (I am not sure about this - if you are sure you should believe this answer much more).
'in' is an insertion indicator.
'celebration' becomes 'revel' (revel is a kind of celebration).
'a' put inside 'revel' is 'REVEAL'.
Can you help me to learn more?
(Other definitions for reveal that I've seen before include "Spill beans" , "Divulge; make visible" , "Tell the truth" , "Leak" , "Remove cover or expose to view" .)