Expert help over lethargy (6)

I believe the answer is:

acedia

'lethargy' is the definition.
(thesaurus)

'expert help over' is the wordplay.
'expert' becomes 'ace' (ace is a kind of expert).
'help' becomes 'aid' ('aid' can be a synonym of 'help'**).
'over' is a reversal indicator.
'aid' reversed gives 'dia'.
'ace'+'dia'='ACEDIA'

(Another definition for acedia that I've seen is " sloth".)

I've seen this clue in The Independent.

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