Fellow's article upfront on Dunfermline's No 1 source of riches maybe (8)
I believe the answer is:
theodore
'dunfermline's no 1 source of riches maybe' is the definition.
I can't judge whether this definition defines the answer.
'fellow's article upfront on' is the wordplay.
'fellow's' becomes 'odo' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'article' becomes 'the' (the definite article in English).
'upfront' is a charade indicator (letters next to each other) (some letters go in front of others).
'on' becomes 're' ('on' can be mean 'with reference to').
'odo' after 'the' is 'theodo'.
'theodo'+'re'='THEODORE'
Can you help me to learn more?
(Other definitions for theodore that I've seen before include "ex-president was named thus" , "Man" , "... Roosevelt" .)