You previously accepted right number (5)
I believe the answer is:
three
'number' is the definition.
(three is a number)
'you previously accepted right' is the wordplay.
I cannot quite see how this works, but
'right' could be 'r' (common abbreviation) and 'r' is present in the answer.
'you' could be 'thee' (I've seen this before) and 'thee' is found in the remaining letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for three that I've seen before include "Small number that still makes a crowd?" , "Number that's a crowd" , "Number of feet in a yard" , "Number constituting a crowd?" , "III" .)