Dry boring part's cut in two (6)
I believe the answer is:
bisect
'cut in two' is the definition.
('bisect' can be a synonym of 'cut in two')
'dry boring part's' is the wordplay.
'dry' becomes 'sec' ('sec' can be similar in meaning to 'dry').
'boring' means one lot of letters goes inside another (some letters must 'bore' a hole into other letters).
'part' becomes 'bit' (bit is a kind of part).
'sec' placed into 'bit' is 'BISECT'.
(Other definitions for bisect that I've seen before include "Halve (angle)" , "Cut equally in two" , "Split exactly in two" , "Cut twenty [IN TWO]" , "Divide in half" .)