Blasphemes (6)
I believe the answer is:
swears
'blasphemes' is the definition.
('swear' can be a synonym of 'blaspheme')
This is the entire clue.
(Other definitions for swears that I've seen before include "Blinds" , "Takes oath or curses" , "Takes oath or utters imprecation (6)" , "Curses or pledges" , "Quite (mus.); a female voice" .)