As the labourers see it, excellent head on pint of stout (5)
I believe the answer is:
plump
'stout' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for plump that I've seen before include "Not obese, just pleasantly rounded" , "Having a full rounded shape" , "stout" , "Fat - set down unceremoniously" , "Buxom, chubby" .)