Commoners' vegetables beside unopened larder (9)
I believe the answer is:
peasantry
'commoners'' is the definition.
(thesaurus)
'vegetables beside unopened larder' is the wordplay.
'vegetables' becomes 'peas' (peas are a type of vegetable).
'beside' says to put letters next to each other (I've seen this in other clues).
'unopened' means to remove the first letter (without opening letter).
'larder' becomes 'pantry' (synonyms).
'pantry' with its first letter taken off is 'antry'.
'peas'+'antry'='PEASANTRY'
(Other definitions for peasantry that I've seen before include "Bumpkins" , "Uncivilised lot" , "Poor folk" , "Agricultural workers as a class" .)