Losing what Unite accepts (6)

I believe the answer is:

behind

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'losing' is the definition.
(synonyms)

'what unite accepts' is the wordplay.
'what' becomes 'eh' (sound used to ask 'what?' or 'pardon?').
'unite' becomes 'bind' (I am not sure about this - if you are sure you should believe this answer much more).
'accepts' indicates putting letters inside.
'eh' inserted inside 'bind' is 'BEHIND'.

Can you help me to learn more?

(Other definitions for behind that I've seen before include "At the back of" , "Astern" , "Taking place in secret" , "in van? No" , "Posterior, derriere" .)

I've seen this clue in The Independent.

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