Split from sexually open-minded cult? (6)
I believe the answer is:
bisect
'split' is the definition.
(I've seen this before)
'sexually open-minded cult?' is the wordplay.
'sexually open-minded' becomes 'bi' (bisexual).
'cult?' becomes 'sect' (religious sect).
'bi'+'sect'='BISECT'
'from' acts as a link.
(Other definitions for bisect that I've seen before include "create schism?" , "Divide into two equal parts" , "Cut twenty [IN TWO]" , "Cut equally in two" , "cross" .)