How to conjugate irregular -IR verbs in Portuguese

verbos irregulares em -ir

This post is about some verbs ending in -IR, they are the verbs in the third conjugation.

And what’s special about them that they deserve a post?

They are “kind of” irregular but not so much… sorry about that! Let’s see examples because it’ll be easier to understand.

Remember the conjugation of ASSISTIR in the Present Simple? It’s regular: Eu assisto / você, ele, ela assiste / nós assistimos / vocês, eles, elas assistem. And Present Subjunctive: eu assista / você, ele, ela assista / nós assistamos / vocês, eles, elas assistam. It keeps the same root and only the ending changes (after the “t”).

First group

What happens to the verbs below is different. Let’s use the verb preferir in the Present Simple as an example:

verbos irregulares em -ireu prefiro –> oops!
você, ele, ela prefere
nós preferimos
vocês, eles, elas preferem

The root of preferir is this part: prefer- . In the first person (eu) there was a change from “e” to “i” but this change doesn’t repeat in você, nós, eles, etc, nor in the other tenses: preferi, preferia, preferisse, etc. It repeats in Present Subjunctive, though.

As Present Subjunctive conjugates from the first person singular Present Indicative (eu prefiro) it’s all irregular. And there are some irregularities in Imperative as well.

eu prefira
você, ele, ela prefira
nós prefiramos
vocês, eles, elas prefiram


Below you can find some verbs from this group, most of them are not so frequent, but others are:

aderir, advertir, aferir, conferir, conseguir, convergir, deferir, digerir, divergir, divertir, ferir, gerir, inferir, ingerir, interferir, perseguir, preferir, proferir, prosseguir, referir, refletir, repetir, seguir, sentir, servir, sugerir, transferir, vestir

I put some verbs in bold because I believe they are more used, but it also depends on why a student is learning Portuguese. For a gastroenterologist the verbs digerir and ingerir may be very important.

Second group

In this group of verbs the change happens in almost the whole Simple Present conjugation. Agredir is a verb in this group, it has “e” in the root, but check the conjugation:

eu agrido
você, ele, ela agride
nós agredimos –> this is the only regular!
vocês, eles, elas agridem

It’s also irregular in the Present Subjunctive and Imperative!


There aren’t many verbs in this group. Check some here:

agredir, denegrir, prevenir, progredir, regredir, transgredir

Third group

verbos irregulares em -irThis group changes a bit because there is an “o” in the root. Dormir is a very frequent verb in this group, so let’s see what happens to this one!

eu durmo –> oops!
você, ele, ela dorme
nós dormimos
vocês, eles, elas dormem

This one is like the first group, but the “o” in the root changes to “u” in the first person singular Present Simple. Of course it’s also irregular in the Present Subjunctive and Affirmative. Check it below:

eu durma
você, ele, ela durma
nós durmamos
vocês, eles, elas durmam


Frequent verbs are part of this group, like:

cobrir, descobrir, dormir, encobrir, engolir, recobrir, tossir

Fourth group

This group is also about vowels “o” and “u” but they work more like the second group. Let’s use subir as an example:

eu subo
você, ele, ela sobe –> oops!
nós subimos
vocês, eles, elas sobem –> oops!

And the Present Subjunctive is all… can you guess?! Regular!!


Some verbs in this group are:

acudir, bulir, consumir, cuspir, escapulir, fugir, sacudir, subir


My tip if you find them hard to memorize: learn the ones you use the most! Write down sentences with them, but make sure the sentences are useful for you!

And you can also practice with the exercise below!

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Let me know if it’s all clear and if you did well in the exercises!

Até a próxima! 🙂

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