Eccentric bit of syncopation (7)

I believe the answer is:

offbeat

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'eccentric' is the definition.
(offbeat means eccentric or unexpected)

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for offbeat that I've seen before include "Unusual or unconventional - perhaps in music" , "Way-out" , "Bohemian" , "Wacky, eccentric" , "Kooky" .)

I've seen this clue in The Daily Express.

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