stalker

[ staw-ker ]
/ ˈstɔ kər /

noun

a person who pursues game, prey, or a person stealthily.
a person who harasses another person, as a former lover, a famous person, etc., in an aggressive, often threatening and illegal manner: Hollywood stars often have security guards to keep dangerous stalkers at bay.

Origin of stalker

stalk2 (verb) + -er1
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for stalker