From Teflpedia

-ism (/ɪzm/) is an English suffix that means "taking side with" or "imitation of", and is often used to describe philosophies, theories, religions, social movements, artistic movements and behaviours[1]

Within teaching, -ism is a PARSNIP, i.e. any word ending in this is likely to be a taboo subject.

See behaviourism, native speakerism for some Teaching-specific isms. And feminism for one more general.

The -ism suffix is related to the suffix -ist, which generally means "a follower of an -ism", e.g. a feminist follows feminism, but can also mean one who does (e.g. scientist).