1. a persistent tormentor

(hypernym) tormentor , tormenter , persecutor

(derivation) harass , hassle , harry , chivy , chivvy , chevy , chevvy , beset , plague , molest , provoke

2. a persistent attacker; "the harassers were not members of the regular army"

(synonym) harrier

(hypernym) attacker , aggressor , assailant , assaulter

(derivation) harass