It means refusal, always (5)
I believe the answer is:
never
'it' is the definition.
The definition suggests a singular noun but the answer is not.
'refusal always' is the wordplay.
'refusal' becomes 'n' (I can't justify this - if you can you should give a lot more credence to this answer).
'always' becomes 'ever' (synonyms).
'n'+'ever'='NEVER'
'means' is the link.
Can you help me to learn more?
(Other definitions for never that I've seen before include "'It's now or - - ' (14 song)" , "Strong negative" , "Not in a month of Sundays" , "' - - Say - - Again': Bond film" , "Not ever" .)