The present passive infinitive presents its subject as undergoing an action simultaneous with the governing verb: amārī “to be loved,” regī “to be ruled,” audīrī “to be heard.” It marks voice and relative time, but it has no person, number, or gender endings. An expressed subject in indirect statement is accusative; an agent, when needed, is normally ā/ab plus ablative.
All unlabelled patterns below are normal Classical prose. English “to be + participle” is often an accurate translation, but Latin syntax—not the presence of English “be”—determines the form.
Formation by Conjugation
First, second, and fourth conjugations replace active infinitive final -e with -ī. Third-conjugation verbs, including third-conjugation -iō verbs, replace the entire active ending -ere with -ī.
| Class | Present active | Present passive | Meaning |
|---|---|---|---|
| 1st | amāre | amārī | to be loved |
| 2nd | monēre | monērī | to be warned |
| 3rd | regere | regī | to be ruled |
| 3rd -iō | capere | capī | to be captured |
| 4th | audīre | audīrī | to be heard |
The third conjugation is the trap: regī, not regerī; capī, not caperī. Macrons distinguish amārī and monērī, while the single ī of regī carries the passive-infinitive ending.
Frequent irregular forms include ferrī “to be carried” and fierī “to be made / happen.” Fierī supplies the present-system passive of faciō but also has the intransitive meaning “happen, become.” Esse and posse have no ordinary passive infinitives because their lexical meanings do not form personal passives.
Haec epistula sine difficultāte legī potest.
This letter can be read without difficulty.
Pōns ante hiemem reficī dēbet.
The bridge ought to be repaired before winter.
The Core Contrast: Who Acts?
Compare active servum laudāre with passive servum laudārī. In indirect statement, servum is accusative in both, but its semantic role changes.
Dīcit servum dominum laudāre.
He says that the enslaved man is praising the master.
Dīcit servum ā dominō laudārī.
He says that the enslaved man is being praised by the master.
In the active sentence, servum performs laudāre and dominum is its object. In the passive sentence, servum undergoes laudārī and ā dominō identifies the agent. English word order helps here, but the Latin endings and preposition are decisive.
An active transitive verb’s accusative object becomes the nominative subject of a finite passive clause: dominus servum laudat → servus ā dominō laudātur. Inside indirect statement, that same passive subject becomes accusative because every expressed infinitive subject is accusative: dīcit servum laudārī.
Relative Time in Indirect Statement
“Present” again means simultaneous with the reporting verb. It does not guarantee present time from the speaker’s perspective.
Nūntius dīcit urbem oppugnārī.
The messenger says that the city is being attacked.
Nūntius dīxit urbem oppugnārī.
The messenger said that the city was being attacked.
Latin keeps oppugnārī in both sentences. English backshifts “is being attacked” to “was being attacked” after dīxit. A perfect passive infinitive would instead mark anterior action: dīxit urbem oppugnātam esse “he said that the city had been attacked.”
This distinction can change the event structure. Present aedificārī shows construction in progress at report time; perfect aedificātam esse presents construction as already completed.
Architectus affirmat domum aedificārī.
The architect states that the house is being built.
See Passive Indirect Statement for personal and impersonal variants.
Complementary Infinitives
A passive infinitive can complete verbs of ability, obligation, beginning, ceasing, and permission. The finite verb may remain impersonal or agree with the patient, depending on its own syntax.
Iānua aperīrī nōn potest; sera frācta est.
The door cannot be opened; the lock is broken.
Captīvī sine vulnere līberārī cupiunt.
The captives want to be freed without injury.
In captīvī ... cupiunt, the nominative captives are subject of the finite verb and understood subject of passive līberārī. They want to undergo the freeing. The infinitive itself does not change for masculine plural agreement.
With defective coepī, Classical Latin commonly aligns the governing verb with a passive infinitive: domus reficī coepta est “the house began to be repaired.” The participle coepta agrees with domus, but reficī still does not agree.
Viae post tempestātem reficī coeptae sunt.
The roads began to be repaired after the storm.
Impersonal Passives of Intransitive Verbs
Latin can also passivize an intransitive verb impersonally. Such an infinitive has no personal patient to put in the accusative: it presents the activity as occurring without naming its performers.
Dīcit in forō pugnārī.
He says that fighting is going on in the forum.
Here pugnārī is passive in form, but “to be fought” is poor English. The idiomatic translation is “fighting is going on” or “people are fighting.” This construction is an important exception to the useful beginner shortcut that every passive infinitive has an expressed thing undergoing the action.
Agents and Instruments
A personal agent is normally ā/ab + ablative: ā medicō cūrārī “to be treated by the doctor.” An instrument or means uses the bare ablative: medicāmentō cūrārī “to be treated with medicine.” English uses “by” much more broadly, so copying the English preposition can obscure the distinction.
Aeger ā medicō medicāmentō novō cūrārī dēbet.
The patient ought to be treated by the doctor with a new medicine.
Here ā medicō is the acting person; novō medicāmentō is the means. The dative of agent belongs especially with the gerundive of obligation and is not the default agent construction for an ordinary present passive infinitive. Compare the dedicated Ablative of Agent.
Deponents: Passive Shape, Active Meaning
Deponent infinitives such as loquī “to speak,” sequī “to follow,” and proficīscī “to set out” have passive morphology but active lexical meaning. They are not present passive infinitives semantically, and they cannot be turned active by restoring -ere.
Mārcus clārē loquī potest, sed nunc tacēre māvult.
Marcus can speak clearly, but now he prefers to be silent.
In loquī, Marcus performs the speaking. A learner must combine morphological parsing (“passive-shaped”) with the dictionary fact (“deponent, active meaning”). There is no purely visual shortcut.
Some ordinary passive forms also acquire lexical translations. Vidērī may mean “to be seen,” but with a predicate it often means “to seem”: beātus vidētur “he seems happy.” The form remains passive historically and morphologically even when idiomatic English has no passive wording.
Archaic and Poetic -ier
Early Latin and poetry sometimes use a present passive infinitive ending -ier, as in dīcier beside dīcī “to be said.” This is (archaic/literary), not a productive alternative for ordinary Classical prose. Meter or imitation of old style can motivate it; learners should recognize it but produce the standard forms.
The specialized history and distribution appear on Archaic Passive Infinitive in -ier.
No Agreement—and Why That Matters
The present passive infinitive is one word and never agrees with its subject: puerum laudārī, puellam laudārī, puerōs laudārī, puellās laudārī. Gender and number become visible in the perfect passive infinitive because a participle is then present: puellam laudātam esse, puerōs laudātōs esse.
Common Mistakes
Keeping -er- in third-conjugation forms
❌ Urbs regerī nōn potest.
Incorrect — third-conjugation regere forms its passive infinitive in -ī.
✅ Urbs regī nōn potest.
The city cannot be ruled.
Using a nominative subject in indirect statement
❌ Dīcit urbs oppugnārī.
Incorrect — the expressed subject of an infinitive in indirect statement is accusative.
✅ Dīcit urbem oppugnārī.
He says that the city is being attacked.
Making the infinitive agree
❌ Viae refectae esse dēbent.
Incorrect for present obligation — this perfect passive infinitive says that the roads ought to have been repaired.
✅ Viae reficī dēbent.
The roads ought to be repaired.
Reading a deponent as passive
❌ Mārcus vult loquī.
Incorrectly translated ‘Marcus wants to be spoken’ — loquor is deponent, so loquī has active meaning.
✅ Mārcus vult loquī.
Marcus wants to speak.
Key Takeaways
- First, second, and fourth conjugations use stem + -rī; third-conjugation verbs use -ī.
- The present passive infinitive marks action simultaneous with its governing verb, not absolute present time.
- In indirect statement, its expressed subject is accusative; a personal agent is normally ā/ab plus ablative.
- It never agrees. Participial agreement signals a different form, especially the perfect passive infinitive.
- Deponents have passive shape but active meaning, and archaic -ier is for recognition rather than neutral production.
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Start learning Latin →Related Topics
- Present Active InfinitiveA2 — How Latin forms and uses the present active infinitive for simultaneous active events, verbal complements, subjects, and indirect statement.
- Perfect Passive InfinitiveA2 — How participial agreement and esse express an event already undergone by the infinitive's subject.
- Passive Indirect StatementB1 — How Latin reports that something is being done, has been done, or will be done with an accusative subject and a passive infinitive.
- Active and Passive VoiceA1 — Understand how Latin changes verb endings and clause structure to present a participant as actor or receiver of an action.