Possibly drill bit without resistance (6)
I believe the answer is:
pierce
'possibly drill' is the definition.
(I've seen this before)
'bit without resistance' is the wordplay.
'bit' becomes 'piece' (synonyms).
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
'resistance' becomes 'r' (electronics abbreviation).
'piece' placed around 'r' is 'PIERCE'.
(Other definitions for pierce that I've seen before include "Not established as fact" , "Make hole in with sharp object" , "Penetrate as with pin" , "Penetrate with a sharp instrument" , "Thrust" .)