stalking = مضايقة وتحرش

التحرش

is one of the meanings of this word

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Note added at 19 mins (2010-01-03 23:41:11 GMT)
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متحرش

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Note added at 31 mins (2010-01-03 23:53:04 GMT)
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Context is needed though!

Stalking
Like domestic violence, stalking is a crime of power and control. Stalking is conservatively defined as "a course of conduct directed at a specific person that involves repeated (two or more occasions) visual or physical proximity, nonconsensual communication, or verbal, written, or implied threats, or a combination thereof, that would cause a reasonable person fear" (Tjaden and Thoennes,1998). Stalking behaviors also may include persistent patterns of leaving or sending the victim unwanted items or presents that may range from seemingly romantic to bizarre, following or laying in wait for the victim, damaging or threatening to damage the victim's property, defaming the victim's character, or harassing the victim via the Internet by posting personal information or spreading rumors about the victim. The overwhelming majority of victims are women (78 percent), and the majority of offenders (87 percent) are men. Nearly 60 percent of women and 30 percent of men are stalked by a current partner (Tjaden and Thoennes, 1998).

There's also "cyberstalking"
Good luck