Favourable source of oil arranged (4-8)
I believe the answer is:
well-disposed
'favourable' is the definition.
Both the answer and definition are adjectives. Maybe they are linked in a way I don't understand?
'source of oil arranged' is the wordplay.
I cannot really see how this works, but
'source' could be 'well' (well is a kind of source) and 'well' is present in the answer.
'of' could be 'o' and 'o' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for well-disposed that I've seen before include "Inclined to be friendly" , "Favourable (towards)" .)