A referee enters wearing football shoes — or not? (10)

'not?' is the definition.
Both the definition and answer are adverbs. Maybe you can see a link between them that I don't see?

'a referee enters wearing football shoes' is the wordplay.
'referee' becomes 'ref' ('ref' can be a synonym of 'referee').
'enters' means one lot of letters goes inside another.
'wearing football shoes' becomes 'booted' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a'+'ref'='aref'
'aref' inserted within 'booted' is 'BAREFOOTED'.

'or' is the link.

Can you help me to learn more?