Former partner with a pit to inspect (7)
I believe the answer is:
examine
'to inspect' is the definition.
(I've seen this before)
'former partner with a pit' is the wordplay.
'former partner' becomes 'ex' (an ex-partner).
'with' says to put letters next to each other.
'pit' becomes 'mine' (mining pit).
'ex'+'a'+'mine'='EXAMINE'
(Other definitions for examine that I've seen before include "Scrutinise, subject to test" , "Question (a witness)" , "vet" , "Closely study" , "Inspect , test" .)