Imperfect Subjunctive — Irregular Forms

Portuguese has about fifteen verbs whose preterites are famously irregular — ser, ir, ter, estar, fazer, poder, saber, querer, dizer, trazer, ver, vir, pôr, dar, haver. Their imperfect subjunctives inherit those irregular stems, but the underlying recipe is unchanged: take the 3rd person plural preterite, drop -ram, add the -sse endings. Once you have the preterite memorized, the imperfect subjunctive comes free.

This page covers the fifteen essential irregular imperfect subjunctives and clears up the most famous trap: ser and ir share the same imperfect subjunctive form (fosse), and only context tells you which is meant.

The pattern, briefly

1. Find the 3pl preterite.
2. Drop the -ram.
3. Add -sse, -sses, -sse, -ssemos, -ssem.
4. In the nós form, add a written accent on the stem vowel. The irregular verbs use the acute (tivéssemos, fizéssemos, quiséssemos, puséssemos) — except ser/ir, which uses the circumflex (fôssemos) because the o is closed.

ser and ir — the great collision

The biggest surprise for learners is that ser (to be) and ir (to go) have the same preterite: fui, foste, foi, fomos, foram. That means they have the same imperfect subjunctive too. Fosse can mean either "were" or "went"; only context disambiguates.

Note the circumflex on the nós form: fôssemos. This is because the o here is closed (/o/ as in avô), and the stress falls on it.

Note how the first and third sentences use fosse / fôssemos from ser, and the second and fourth use them from ir. The verb forms are identical; the meaning is a matter of interpretation.

ter (to have) — 3pl preterite tiveram

Notice the acute (´) on tivéssemos — and likewise on the nós forms of the other irregulars below: fizéssemos, pudéssemos, soubéssemos, quiséssemos, disséssemos, puséssemos. All follow the same pattern. Contrast this with regular -er verbs, which take a circumflex: comêssemos, bebêssemos. The difference is a point of conventional Portuguese orthography and simply has to be memorized.

Tivesse is almost certainly the single most useful imperfect subjunctive form in the language, because it is also the auxiliary for the pluperfect subjunctive: tivesse + past participle gives you "would have had," "if I had done," etc.

estar (to be, state) — 3pl preterite estiveram

fazer (to do / make) — 3pl preterite fizeram

poder (to be able to) — 3pl preterite puderam

Notice the u — the preterite of poder is pude, pudeste, pôde, pudemos, puderam (the 3sg pôde carries a circumflex to distinguish it from the present pode, but this distinction does not survive into the subjunctive).

saber (to know) — 3pl preterite souberam

querer (to want) — 3pl preterite quiseram

dizer (to say) — 3pl preterite disseram

The shorter set: fewer forms, same rule

The following verbs are irregular but less frequently needed in full paradigm. For each, remember the rule: 3pl preterite → drop -ram → add endings, with accent on the nós form.

trazer (to bring)

3pl preterite: trouxeram (note the spelling with x — pronounced /s/). Stem: trouxe-

ver (to see)

3pl preterite: viram → stem vi-

vir (to come)

3pl preterite: vieram → stem vie-

pôr (to put)

3pl preterite: puseram → stem puse-

All of pôr's compounds (compor, depor, dispor, impor, propor, supor, transpor) follow the same pattern: compusesse, dispusesse, propusesse, supusesse, etc.

dar (to give)

3pl preterite: deram → stem de-

haver (to have, impersonal; auxiliary)

3pl preterite: houveram → stem houve-

Haver in modern European Portuguese mostly appears impersonally (há, havia, houve = "there is / was"). The impersonal imperfect subjunctive is houvesse, meaning "there were / existed (hypothetically)." In literary and biblical Portuguese, haver also still serves as the auxiliary for compound subjunctive tenses (houvesse feito), but everyday speech uses tivesse feito instead.

Quick reference: all fifteen in one place

Distinguishing ser and ir in practice

Since fosse is ambiguous, context has to do the work. Here is how you can tell, with confidence:

1. If there is a noun phrase or adjective after the verb, it is usually ser. Se ele fosse médico = if he were a doctor (ser). Se fôssemos ricos = if we were rich (ser).
2. If there is a place or direction after the verb, it is usually ir. Se ela fosse a Lisboa = if she went to Lisbon (ir). Que eu fosse ao supermercado = that I went to the supermarket (ir).
3. If the sentence is about an action or motion, it is ir. Queria que fosses comigo = I wanted you to come with me (ir).
4. If the sentence is about identity, state, or description, it is ser. Se eu fosse tu = if I were you (ser).

Compound tenses built on the imperfect subjunctive

Once you have tivesse, you can build the pluperfect subjunctive (mais-que-perfeito do conjuntivo): tivesse + past participle. This expresses counterfactuals about the past — things that did not happen but could have.

Older and more literary Portuguese also allows houvesse + past participle for the same meaning: se houvesse estudado, teria passado. This is recognizable but not common in modern speech. For typical European Portuguese, tivesse + past participle is the default.

Register and recognition

All of these irregular imperfect subjunctives are fully everyday. You will hear se fosse tu, se tivesse tempo, se pudesse, se quisesses in any casual conversation. They are not formal, literary, or "advanced" in register — they are simply the only way to express the meanings they carry.

One exception is the literary construction fora (archaic pluperfect of ser/ir) used instead of tivesse sido / tivesse ido. You will encounter fora in classical literature (Camões, Pessoa) but almost never in modern speech. It is worth recognizing; you do not need to produce it.

Common Mistakes

Era describes something that actually happened or was habitually true in the past. Fosse describes a hypothetical state. For "if I were X," always fosse.

After queria que, the embedded verb must be imperfect subjunctive. Tinhas is the imperfect indicative and does not carry the subjunctive mood that the structure requires.

Another easy trap: sabia (imperfect indicative — "I used to know") vs soubesse (imperfect subjunctive — "(if) I knew"). The hypothetical meaning always demands soubesse.

Sequence of tenses with irregular verbs: past main verb (pediu) → imperfect subjunctive in the dependent clause (pusesse). Not the present indicative (ponho), not the present subjunctive (ponha).

The conditional goes in the main clause, not the se-clause. The se-clause always takes the imperfect subjunctive in hypothetical structures.

Key takeaways

• Every irregular imperfect subjunctive is built from the 3pl preterite of an irregular verb: foram → fosse, tiveram → tivesse, puseram → pusesse.
• The nós form always carries a written accent: fôssemos, tivéssemos, pudéssemos, puséssemos, soubéssemos.
• Ser and ir share the same imperfect subjunctive form — fosse. Context tells you which.
• Tivesse is the auxiliary for the pluperfect subjunctive (tivesse feito, tivesse sido) — the most important compound subjunctive.
• These forms are fully everyday; you hear them constantly in polite and casual speech, not only in formal writing.

Next: cement these forms in the hypothetical structure on the if-clauses page, or go back to the regular forms to compare.