Chivvy (6)
I believe the answer is:
harass
'chivvy' is the definition.
(I know that chivvy can be written as harass)
This is all the clue.
(Other definitions for harass that I've seen before include "bug" , "Vex - pester" , "Intimidate, torment" , "Repeatedly torment" , "Constantly torment" .)