Clearly no motiveless crime! (7)

I believe the answer is:

treason

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'crime' is the definition.
(treason is a kind of crime)

I cannot understand how the rest of the clue works.

(Other definitions for treason that I've seen before include "One's art? (anag)" , "Betrayal (of one's country)" , "Disloyalty (to one's country)" , "Betraying one's country" , "Crime of disloyalty" .)

I've seen this clue in the Evening Standard.

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