One lies but fails to be devious (8)

I believe the answer is:

fabulist

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'one lies but fails to be devious' is the definition.
I can't tell whether this definition defines the answer.

'but fails to be devious' is the wordplay.
'to be devious' is an anagram indicator.
'but'+'fails'='butfails'
'butfails' anagrammed gives 'FABULIST'.

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I've seen this clue in The Sunday Times and The Times.

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