Colleagues -- excellent people -- swallowing old whiskey (2-7)

I believe the answer is:

co-workers

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'colleagues' is the definition.
('co-worker' can be a synonym of 'colleague')

'excellent people swallowing old whiskey' is the wordplay.
'excellent people' becomes 'corkers' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'swallowing' indicates putting letters inside.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'whiskey' becomes 'W' (alpha bravo charlie delta ...).
'o'+'w'='ow'
'corkers' going around 'ow' is 'CO-WORKERS'.

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I've seen this clue in The Telegraph.

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