Fail to justify inconclusive opinion (5)

I believe the answer is:

belie

'fail to justify' is the definition.
(I've seen this before)

'inconclusive opinion' is the wordplay.
'inconclusive' means to remove the last letter.
'opinion' becomes 'belief' (I've seen this before).
'belief' with its final letter taken away is 'BELIE'.

(Other definitions for belie that I've seen before include "Contradict" , "Show to be untrue" , "Confute" , "Fail to justify" .)

I've seen this clue in The Telegraph.

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