To begin with, 'anon' means in the future (4)
I believe the answer is:
away
'future' is the definition.
Both the definition and answer are adjectives. Maybe you can see an association between them that I can't see?
'to begin with anon means' is the wordplay.
'to begin with' indicates taking the first letters.
'means' becomes 'way' (a way or means of doing something).
The initial letter of 'anon' is 'a'.
'a'+'way'='AWAY'
'in the' acts as a link.
Can you help me to learn more?
(Other definitions for away that I've seen before include "(Of match) not home" , "football result!" , "Non-home match" , "Missing" , "Away in the distance" .)