Old and sullen, making smell (5)
I believe the answer is:
odour
'smell' is the definition.
(I know that smell can be written as odour)
'old and sullen' is the wordplay.
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'and' is a charade indicator (letters next to each other).
'sullen' becomes 'dour' (synonyms).
'o'+'dour'='ODOUR'
'making' acts as a link.
(Other definitions for odour that I've seen before include "Any property detected by the olfactory system" , "Aroma or fragrance" , "Smell, redolence" , "Smell; repute" , "Distinctive smell" .)