In English grammar, verbs are irregular if they don’t have the conventional ‘-ed’ ending in the past tense and/or past participle forms. These verbs do not follow the usual rules for verb forms. Their conjugation follows a different pattern. They are also known as strong verbs. Simply, an irregular verb is any verb that does not follow the general rule of using “-ed” at the end of the word to make the past tense or the past participle form.