New stage in harassment (7)
I believe the answer is:
teasing
'harassment' is the definition.
(teasing is a kind of harassment)
'new stage in' is the wordplay.
'new' indicates an anagram.
'stage'+'in'='stagein'
'stagein' with letters rearranged gives 'TEASING'.
(Other definitions for teasing that I've seen before include "Tantalising" , "Annoying" , "Combing wool and irritating playfully" , "Vexing playfully" , "Making fun of in a playful way" .)