Digging, so to speak
I believe the answer is:
into
'digging so to speak' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for into that I've seen before include "Keen on, colloquially" , "Knowledgeable about" , "Curious about" , "Taking an active and lively interest (in something)" , "Showing enthusiasm for" .)