Warmth of a river — one in Portugal mostly (6)
I believe the answer is:
ardour
'warmth' is the definition.
(I have seen 'Warmth of feeling' mean 'ardour' so perhaps 'warmth' could also mean 'ardour')
'a river one in portugal mostly' is the wordplay.
I cannot quite understand how this works, but
'a' is within the answer.
'river' could be 'r' (abbreviation) and 'r' is found within the answer.
'one' could be 'o' (I've seen this in other clues) and 'o' is found within the answer.
This explanation may well be incorrect...
'of' is the link.
Can you help me to learn more?
(Other definitions for ardour that I've seen before include "Love and enthusiasm" , "causing some heat" , "Fervour or passion" , "Intense eagerness" , "Passionate warmth" .)