Best digger (4)
I believe the answer is:
pick
I believe this is a double definition.
'best' is the first definition.
(the best possible pick or selection)
'digger' is the second definition.
(tool used when digging)
(Other definitions for pick that I've seen before include "Choose - ground-breaking instrument" , "Choose, select" , "tool - it breaks" , "hacker?" , "Cream" .)