Fizzy tea? It's absurd (7)
I believe the answer is:
charade
'fizzy tea? it's absurd' is the definition.
I can't tell whether this definition defines the answer.
'tea? it's absurd' is the wordplay.
'tea?' becomes 'char' (I've seen this before).
'it's absurd' becomes 'ade' (I can't explain this - if you can you should give a lot more credence to this answer).
'char'+'ade'='CHARADE'
Can you help me to learn more?
(Other definitions for charade that I've seen before include "Ridiculous pretence" , "Travesty, mockery" , "Pretence; parlour game" , "Pretence - travesty" , "An absurd pretence, or a guessing game" .)