From Teflpedia

An insult (/ɪnsʌlt/) is an expression or statement (or sometimes behaviour) which is disrespectful or scornful. Insults may be intentional or accidental.[1]

It is an important part of language, and may therefore be learned by or taught to students.

Deliberate insults may be banned in certain situations, such as debates, by discourse standards.

There is also "damning with faint praise"

Many in the TEFL industry would consider their salaries to be an insulting