Irregular
The term 'irregular' is used to describe any word that changes it's form in a way that isn't standard or like most words.This term is most commonly applied to verbs to distinguish those verbs that don't belong the regular groups -er, -ir, and others. However, adjectives and adverbs can be irregular too.
Irregular verbs tend to be the verbs that are most common. The four most important irregular French verbs are:
- être (to be)
- avoir (to have)
- faire (to do/make)
- aller (to go)