Stop a man with a packet coming from the supermarket (9)

I believe the answer is:

detergent

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'a packet coming from the supermarket' is the definition.
I can't tell whether this definition defines the answer.

'stop a man' is the wordplay.
'stop' becomes 'deter' (to deter behaviour is to stop it).
'a man' becomes 'gent' (gent is a kind of man).
'deter'+'gent'='DETERGENT'

'with' is the link.

Can you help me to learn more?

(Other definitions for detergent that I've seen before include "Cleansing substance used for washing clothes" , "Soapless cleanser" , "Get tender (anag)" , "Soluble cleanser" , "Cleansing solvent" .)

I've seen this clue in the Evening Standard.

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