Letter idiot attempted to hide (4)

I believe the answer is:

iota

'letter' is the definition.
(Greek letter)

'idiot attempted to hide' is the wordplay.
'to hide' indicates the answer is hidden within the clue.
'IOTA' can be found hidden inside 'idiot attempted'.

(Other definitions for iota that I've seen before include "Ninthe letter of the Greek alphabet" , "Tiny or scarcely detectable amount" , "Jot or tittle" , "Foreign character" , "Just a jot, from Greek alphabet" .)

I've seen this clue in The Independent.

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