Maintain a resolve (4)

I believe the answer is:

avow

'maintain' is the definition.
(I've seen this before)

'a resolve' is the wordplay.
'resolve' becomes 'vow' (I've seen this in another clue).
'a'+'vow'='AVOW'

(Other definitions for avow that I've seen before include "Solemnly declare" , "Assert, swear" , "Assert/confess openly" , "Declare - admit" , "Solemnly promise" .)

I've seen this clue in the Sydney Morning Herald.

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