Schools are failing to tackle offensive name-calling in schools, and often dismiss it as playground banter, according to a new report into bullying by Ofsted.
A survey of primary and secondary school pupils and teachers by the schools' watchdog found that language used by pupils against their classmates ranged from the "potentially hurtful but quite mild" to "openly derogatory."
But few schools had a clear policy on the use of language or the boundaries between banter and behaviour that can cause individuals to feel threatened or hurt, the report stated.
Words such as "stupid", "idiot", "mong", "spaz" or "retard" were used to describe pupils when they struggled with work or sport.
Primary and secondary school pupils also said the word "gay" was often used as an insult. "It's kind of used to men rubbish," a secondary school pupil explained. Staff also said that the use of the word "gay" as a derogatory term was a common issue.
The Ofsted report was based on visits to 37 primary and 19 secondary schools. Inspectors met with more than 2,000 pupils and teaching staff to look at how effective schools are at preventing and tackling bullying.
Pupils in all of the schools visited could give a range of examples of disparaging language related to perceived ability, race, religion, sexuality, appearance or family circumstances that they had heard at school.
Although many pupils were aware that such language was not acceptable, it was often seen as "just banter."
Teacher training on bullying tended to be general, and did not focus on the different types of bullying that can occur, the report said. Some of the staff interviewed also said that they did not always not feel confident challenging unacceptable language.
However, the best schools had clear expectations and rules on how pupils should interact with each other, which meant they understood the effect bullying could have on others.
Other schools had achieved significant success by working with parents and carers and members of the community to reach a better understanding, the report said.
Susan Gregory, director of education and care, said: "Schools must develop a positive culture so all pupils learn in a happy and safe environment.
"Teachers should receive the right training and support so they have the skills and confidence to teach pupils about diversity and the effects of bullying."