Left with one excellent boy offering cooperation (7)

I believe the answer is:

liaison

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

'left with one excellent boy' is the wordplay.
'left with' becomes 'li' (I can't justify this - if you can you should give a lot more credence to this answer).
'one excellent' becomes 'ai' (resembles 'Al', old-fashioned term for excellent).
'boy' becomes 'son' (male child).
'li'+'ai'+'son'='LIAISON'

'offering' is the link.

Can you help me to learn more?

(Other definitions for liaison that I've seen before include "Mediator" , "entanglement" , "Contact between groups" , "Binding agent of a sauce; secret relationship" , "Secret love-affair" .)

I've seen this clue in The Times.

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