Stops to become regular drinker (7)

I believe the answer is:

tosspot

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'regular drinker' is the definition.
'tosspot' can be an answer for 'drinker' (I have seen 'Habitual drinker' mean 'tosspot' so perhaps 'drinker' could also mean 'tosspot'). I'm not sure about the 'regular' bit.

'stops to become' is the wordplay.
'become' indicates an anagram.
'stops'+'to'='stopsto'
'stopsto' is an anagram of 'TOSSPOT'.

Can you help me to learn more?

(Other definitions for tosspot that I've seen before include "One drinker" , "Habitual drinker" , "One drunkard" , "Drunk (informal)" , "Fool" .)

I've seen this clue in the Sydney Morning Herald.

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