Deny wife gets released from prison once (6)
I believe the answer is:
negate
'deny' is the definition.
(I've seen this in other clues)
'wife gets released from prison once' is the wordplay.
'wife' becomes 'w' (abbreviation).
'gets released from' suggests deleting specific letters.
'prison once' becomes 'newgate' (historical prison).
'newgate' with 'w' taken away is 'NEGATE'.
(Other definitions for negate that I've seen before include "Render null or disprove" , "Opera by Puccini" , "Discredit" , "Disprove or nullify" , "Cause to have no effect" .)