Wit needing fizzy drink to raise energy (6)
I believe the answer is:
esprit
'wit' is the definition.
(esprit can mean being witty)
'fizzy drink to raise energy' is the wordplay.
I cannot quite understand how this works, but
'drink' could be 'it' and 'it' is present in the answer.
'energy' could be 'e' (physics symbol as in E=mc2) and 'e' is found in the answer.
This explanation may well be incorrect...
'needing' acts as a link.
Can you help me to learn more?
(Other definitions for esprit that I've seen before include "French morale as in de corps?" , "Vivacious wit" , "Group morale is . . . . . . de corps" , "Lively wit" , "Lively and vivacious quality" .)