Twitter's stance on bullying and harassment
This can include hurtful language which targets an individual or group of people, trolling, spreading rumours and excluding people from online communities. In the case of harassment, the behaviour is repeated and intended to cause distress. Repeated harassment should be reported to the police.
Twitter does not allow the targeted harassment of someone or inciting others to do so. Twitter consider abusive behaviour an attempt to harass, intimidate, or silence someone else’s voice.