It's pleasant to listen to European impostor (7)

I believe the answer is:

euphony

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'impostor' is the definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.

I don't understand the rest of the clue.

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(Other definitions for euphony that I've seen before include "Sounding nice" , "Pleasantness of sound" , "Agreeable sound" , "what we like to hear" , "Pleasing sound" .)

I've seen this clue in The Independent.

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