Finally dig in (5)
I believe the answer is:
inter
'in' is the definition.
Both the answer and definition are adjectives. Maybe there's an association between them I don't understand?
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for inter that I've seen before include "Bury (or, perhaps, Milan)" , "get put down!" , "Prefix meaning between or among" , "foreign team" , "promoting cessation" .)