Rereads slasher novel for practice (5,9)
I believe the answer is:
dress rehearsal
'practice' is the definition.
(dress rehearsal is a kind of practice)
'rereads slasher novel' is the wordplay.
'novel' indicates an anagram.
'rereads'+'slasher'='rereadsslasher'
'rereadsslasher' is an anagram of 'DRESS REHEARSAL'.
'for' is the link.
(Other definitions for dress rehearsal that I've seen before include "Final play run-through" , "trial run" , "last chance to get things right" , "last practice" , "Strip show doesn't need such" .)