Active barber’s arguing (2,4)

I believe the answer is:

at odds

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'arguing' is the definition.
(I've seen this in another clue)

I cannot understand how the remainder of the clue works.

(Other definitions for at odds that I've seen before include "In conflict with, oppposed to (2,4)" , "In disagreement or dispute" , "On bad terms" , "Conflicting (with)" , "Disagreeing" .)

I've seen this clue in The Guardian.

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