Hand digit (6)
(Other definitions for finger that I've seen before include "Touch; select" , "Fringe (anag.)" , "Slender part attached to the hand" , "shop" , "amount of drink" .)
'hand digit' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for thumb that I've seen before include "First digit" , "The hand's pollex" , "Attempt to obtain a lift" , "Opposable digit" , "Hand digit" .)