A great deal for Trump in South Maine (4)
I believe the answer is:
some
'a great deal' is the definition.
Both the answer and definition are adverbs. Maybe there's a link between them I don't understand?
'for trump in south maine' is the wordplay.
'for trump' becomes 'o' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' is an insertion indicator.
'south' becomes 's' (abbreviation).
'maine' becomes 'me' (abbreviation).
's'+'me'='sme'
'o' placed inside 'sme' is 'SOME'.
Can you help me to learn more?
(Other definitions for some that I've seen before include "An unspecified quantity, not all" , "An undetermined number" , "Several" , "Unknown or unspecified amount or number" , "Hard work" .)