Cut off source of exclusive rum (8)

I believe the answer is:

estrange

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

'source of exclusive rum' is the wordplay.
'source of exclusive' becomes 'e' (I can't explain this - if you can you should believe this answer much more).
'rum' becomes 'strange' (synonyms).
'e'+'strange'='ESTRANGE'

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(Other definitions for estrange that I've seen before include "split up?" , "Divorce" , "Alien" , "Get cut off" , "Lose friendship" .)

I've seen this clue in The Times.

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