Sample of popular variety for grub (5)
I believe the answer is:
larva
'grub' is the definition.
(thesaurus)
'sample of popular variety for' is the wordplay.
'sample of' indicates the answer is hidden within the clue (I've seen this in other clues).
'LARVA' is hidden in the letters of 'popular variety for'.
(Other definitions for larva that I've seen before include "early form" , "Manage" , "Grub of e.g. beetle" , "immature six-footer?" , "nit?" .)