One on the way to the match? (7,5)
I believe the answer is:
wedding guest
'one on' is the definition.
I can't judge whether this definition defines the answer.
'way to the match?' is the wordplay.
'way' becomes 'guest' (I am not sure about this - if you are sure you should believe this answer much more).
'to' means one lot of letters go next to another (I've seen this in other clues).
'the match?' becomes 'wedding' (match can mean a marriage).
'guest' after 'wedding' is 'WEDDING GUEST'.
'the' acts as a link.
Can you help me to learn more?
(Other definitions for wedding guest that I've seen before include "Union non-member" , "target for Coleridge's seaman" .)