Strict tea-user seen sloshed (7)

I believe the answer is:

austere

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'strict' is the definition.
(I've seen this before)

'tea-user seen sloshed' is the wordplay.
'tea-user' can be anagrammed to 'AUSTERE'.
Though, I am unsure how this is indicated.

Can you help me to learn more?

(Other definitions for austere that I've seen before include "Grave, unsmiling" , "Bleak" , "Severely simple and plain in appearance" , "Severe; lacking luxuries" , "Severe in appearance" .)

I've seen this clue in The Telegraph.

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