Suit appropriate for diggers (6)
I believe the answer is:
spades
I believe this is a double definition.
'suit' is the first definition.
(playing card suit)
'for diggers' is the second definition.
(I've seen this before)
'appropriate' acts as a link.
(Other definitions for spades that I've seen before include "Black suit" , "Garden tools and card suit" , "Does some groundwork" , "One of two black suits" , "Digging implements" .)