effervescent (5)
'effervescent' is the definition.
(thesaurus)
This is all the clue.
(Other definitions for gassy that I've seen before include "Verbose" , "Fizzy" , "Carbonated" .)
'effervescent' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for fizzy that I've seen before include "Sparkling (drink)" , "Effervescent" , "Aerated (drink)" .)