Frank is no fibber (6)

I believe the answer is:

honest

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'frank' is the definition.
('honest' can be similar in meaning to 'frank')

I cannot understand how the remainder of the clue works.

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(Other definitions for honest that I've seen before include "Truthful and dependable" , "Free of deceit, truthful by nature" , "Truthful in manner" , "Free of deceit and lies - truly!" , "'Fair-dealing, upright (6)'" .)

I've seen this clue in the Evening Standard.

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