Politics is the subject most likely to provoke bullying insults, followed by sport, according to a study into cyber-bullying and hate speech online.
Most cyber-bullying on Twitter takes place between 5pm and 8pm on a Sunday, and racist language was the most common form of hate speech, the study found.
Other findings included that most insults related to intelligence, with appearance, sexual orientation, religion and gender also used to denigrate.
The study, by Brighton-based anti-bullying charity Ditch the Label in partnership with social intelligence firm Brandwatch, evaluated 19 million tweets from the US and the UK over four years.
The report, published to coincide with anti-bullying week, looks at areas including who is most likely to receive abuse and when people are most likely to experience cyber-bullying.
It found that female trolls tended to use insults relating to intelligence and appearance, while males were more likely to use homophobic insults.
Brandwatch research manager Edward Crook said the data painted a "troubling view" of online abuse but that social networks were also a powerful tool to support bullying victims.
Ditch the Label founder Liam Hackett said: "The data provides a uniquely observational view on the issue of cyber-bullying and hate speech and we will now be using these insights to further develop our support programs and campaigns.
"It's important not to villainise those who use the internet to send abuse, rather we should be trying to understand the root issues."
Meanwhile, in a separate report, the NSPCC said online bullying among young people and children as young as seven has risen by 88% in five years.
Figures show the charity's helpline service Childline counselled 4,541 children about online bullying in 2015/16, compared with 2,410 in 2011/12.
Comments posted on social media profiles, blogs and online pictures ranged from abusive words about appearance to death threats.
NSPCC chief executive Peter Wanless said: "Online bullying is one of the biggest child protection challenges of this generation. It is a problem intensified by the ever-increasing presence of the internet."
More than half of Britons have been bullied in their lifetime, according to a new YouGov survey of 2,000 people for the Diana Award charity anti-bullying campaign.
Nearly half (48%) of young people aged 16 to 24 who had been bullied said listening to music helped them to feel stronger.