Old man on cold stout (6)
I believe the answer is:
chubby
'stout' is the definition.
(thesaurus)
'old man on cold' is the wordplay.
I cannot quite understand how this works, but
'cold' could be 'c' (abbreviation, eg on taps) and 'c' is present in the answer.
'old man' could be 'hubby' (I've seen this in another clue) and 'hubby' is found in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for chubby that I've seen before include "Attractively plump" , "Round and pleasantly plump" , "with some corporation?" , "On the plump side" , "Plumb and round" .)