harass

Short definition from Wiktionary

Verb

1. 1
   To annoy (someone) frequently or systematically; to pester.
2. 2
   To annoy (someone) frequently or systematically; to pester: To persistently bother (someone, or a group of people) physically or psychologically when such behaviour is illegal and/or unwanted, especially over an extended period.
3. 3
   To put excessive burdens upon (someone); to subject (someone) to anxieties.
4. 4
   To trouble (someone, or a group of people) through repeated military-style attacks.
5. 5
   Often followed by out: to fatigue or tire (someone) with exhausting and repeated efforts.

Noun

1. 1
   Harassment; pestering.