Appendix:Latin irregular verbs

The irregular verbs of Latin consist of the following verbs and their compounds. Most do not belong to a particular conjugation, because their second principle parts are irregular. However, dō is said to be in the first conjugation, and sum along with fero are said to be irregular verbs, that is, they do not keep any rule in their conjugation.

sum
Future active participle: futūrus, –a, –um Present active infinitive: esse Future active infinitive: futūrus esse or fore Perfect active infinitive: fuisse Although this verb lacks a present active participle, unusually, derivatives and  have forms absēns and praesēns, but these do not come from the non-existent *sēns (compare ). Another present participle, was used from Medieval Latin.

eō
1—may be iī

fīō
This verb serves as the passive of faciō in the Present System. It lacks a perfect and participial stem, as the Perfect System and the Future Passive Participle are formed regularly from faciō. The vowel i of the stem is long throughout, except in the third singular and before -er.

aiō
aiō, aiiō

Verbs with an irregular short 2nd person singular imperative

 * (2nd person singular imperative )
 * (2nd person singular imperative )
 * (2nd person singular imperative )
 * (2nd person singular imperative )

Verbs with an irregular future active participle

 * (future active participle, not mortuūrus)
 * (future active participle, not ortūrus)
 * (future active participle, not nātūrus)
 * (future active participle, not rutūrus)