Most bubbly girl's beginner, help to suppress energy (8)

I believe the answer is:

gassiest

'most bubbly' is the definition.

'girl's beginner help to suppress energy' is the wordplay.
'beginner' indicates taking the first letters.
'help' becomes 'assist' (assisting is a kind of helping**).
'to suppress' means one lot of letters goes inside another.
'energy' becomes 'e' (physics symbol as in E=mcs).
The first letter of 'girl' is 'g'.
'assist' placed around 'e' is 'assiest'.
'g'+'assiest'='GASSIEST'

I've seen this clue in The Telegraph.

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