Impersonal πρέπει / μπορεί να | Greek Grammar

Two of the most useful modal expressions in Greek behave in a way that surprises English speakers: they never change their form. Whether you, I, or all of us have to do something, the obligation word stays πρέπει; whether the rain, the guest, or the whole plan might happen, the possibility word stays μπορεί. These are impersonal verbs — they have no subject of their own, and the person is expressed entirely by the να-verb that follows. The wider family of subjectless constructions is on impersonal and dummy subjects. Get comfortable with this and you gain a compact, high-frequency way to talk about duty and chance.

πρέπει να — "must / have to"

πρέπει να expresses obligation or necessity. The crucial fact: πρέπει is frozen in the third person singular for every subject. You do not conjugate it; you conjugate the verb after να, and that verb shows who is under the obligation.

Greek	Meaning
πρέπει να φύγω	I have to leave
πρέπει να φύγεις	you have to leave
πρέπει να φύγει	he/she has to leave
πρέπει να φύγουμε	we have to leave
πρέπει να φύγετε	you (pl.) have to leave
πρέπει να φύγουν	they have to leave

One column of the table changes; the other is stone. This is the opposite of English, where the person hangs on the modal ("I must," "we must") and the main verb is a bare infinitive. In Greek the modal is fixed and the second verb does all the person-marking.

Πρέπει να φύγω τώρα, θα χάσω το λεωφορείο.

prépi na fígho tóra, tha cháso to leoforío

I have to leave now, I'll miss the bus.

Πρέπει να δουλέψεις πιο σκληρά αν θες προαγωγή.

prépi na dhulépsis pio sklirá an thes proaghoyí

You have to work harder if you want a promotion.

Πρέπει να προσέχουμε τι λέμε μπροστά στα παιδιά.

prépi na proséchume ti léme brostá sta pedhiá

We have to watch what we say in front of the kids.

μπορεί να — "may / might"

μπορεί να expresses possibility — that something may or might be the case. Like πρέπει, it is invariable: μπορεί stays put whatever the person or thing that might act.

Μπορεί να βρέξει αργότερα, ο ουρανός μαύρισε.

borí na vréksi arghótera, o uranós mávrise

It might rain later, the sky's gone dark.

Μπορεί να μην έρθει καθόλου, δεν είναι σίγουρο.

borí na min érthi kathólu, dhen íne síghuro

He might not come at all, it's not certain.

Χτύπησε το κουδούνι — μπορεί να είναι ο ταχυδρόμος.

chtípise to kudhúni — borí na íne o tachidhrómos

The doorbell rang — it might be the postman.

μπορώ να vs μπορεί να — the trap of one form

Here is where care pays off. μπορεί is, on paper, just the third-person singular of the ordinary verb μπορώ ("to be able"). So the same shape does two different jobs:

Personal μπορώ / μπορείς / μπορεί… ("I can / you can / he can") — a real ability, and the verb conjugates for its subject.
Impersonal μπορεί ("it may be that…") — pure possibility, frozen, no subject.

Μπορώ να σε βοηθήσω αν θέλεις, έχω χρόνο.

boró na se voithíso an thélis, écho chróno

I can help you if you want, I've got time.

Μπορείς να μου δώσεις το αλάτι, σε παρακαλώ;

borís na mu dhósis to aláti, se parakaló;

Can you pass me the salt, please?

Μπορεί να έχει δίκιο, δεν το είχα σκεφτεί έτσι.

borí na échi dhíkio, dhen to ícha skeftí étsi

He may be right — I hadn't thought of it that way.

💡

Because μπορεί serves double duty, a sentence with a third-person subject can be genuinely two-way. Ο Νίκος μπορεί να τρέξει δέκα χιλιόμετρα can mean "Nikos can run 10 km" (ability) or "Nikos might run 10 km" (possibility). Greek leaves it to context and intonation — the ability reading stresses μπορεί, the possibility reading leans on the whole μπορεί-να frame. If you must be unambiguous, use είναι σε θέση να for ability or ίσως for possibility.

Negation — where "not" sits matters

With πρέπει, put δεν in front and you get a prohibition: δεν πρέπει να = "must not / shouldn't."

Δεν πρέπει να τρως τόσο γρήγορα, θα πάθεις κακό.

dhen prépi na tros tóso ghríghora, tha páthis kakó

You shouldn't eat so fast, you'll do yourself harm.

With μπορεί, the placement of the negative changes the meaning sharply. μπορεί να μην = "might not" (a weak possibility of the opposite); δεν μπορεί να = "it can't be that / surely not" (near-certain denial). Both are correct — they say different things.

Μπορεί να μην πεινάει ακόμα, φάγαμε αργά.

borí na min pinái akóma, fághame arghá

He might not be hungry yet, we ate late. (weak — maybe not)

Δεν μπορεί να πεινάει, μόλις έφαγε ένα ολόκληρο πιάτο!

dhen borí na pinái, mólis éfaye éna olókliro piáto!

He can't be hungry, he just ate a whole plateful! (strong — surely not)

The past: έπρεπε να and μπορεί να + past

πρέπει has a single past form, έπρεπε — again invariable. It covers two English meanings depending on the tense inside the clause:

έπρεπε να
- simple past-referring verb is open between two readings — "had to (and did)" and "should have (and didn't)"; only a pluperfect inside the clause forces the regret. See obligation: πρέπει / έπρεπε.
έπρεπε να
- pluperfect (είχα + …) = a counterfactual reproach ("should have," but didn't).

Έπρεπε να δουλέψω και το Σάββατο αυτή τη βδομάδα.

éprepe na dhulépso ke to Sávato aftí ti vdhomádha

I had to work on Saturday this week too.

Έπρεπε να το είχες πει νωρίτερα, τώρα είναι αργά.

éprepe na to íches pi norítera, tóra íne arghá

You should have said so earlier — now it's too late.

For past possibility, keep μπορεί and put the past inside the clause: μπορεί να έφυγε = "he may have left." For past ability or circumstance ("could have"), the modal itself shifts to μπορούσε / μπορούσα.

Μπορεί να έφυγε κιόλας, δεν τον βλέπω πουθενά.

borí na éfiye kiólas, dhen ton vlépo puthená

He may have already left, I don't see him anywhere.

Μπορούσα να είχα πάει, αλλά δεν είχα διάθεση.

borúsa na ícha pái, alá dhen ícha dhiáthesi

I could have gone, but I didn't feel like it.

Other impersonals on the same pattern

A small set of everyday impersonals run identically — frozen verb, person on the να-clause: χρειάζεται να ("it's necessary to / need to"), αξίζει να ("it's worth …-ing"), φαίνεται να ("seems to").

Χρειάζεται να ξεκουραστείς λίγο, δείχνεις εξαντλημένος.

chriázete na ksekurastís lígho, dhíchnis eksandliménos

You need to rest a bit, you look exhausted.

Αξίζει να το δεις από κοντά, οι φωτογραφίες δεν το αποδίδουν.

aksízi na to dhis apó kondá, i fotoghrafíes dhen to apodhídhun

It's worth seeing in person — photos don't do it justice.

Φαίνεται να τα πηγαίνουν καλά οι δυο τους τελευταία.

fénete na ta piyénun kalá i dhio tus teleftéa

The two of them seem to be getting on well lately.

Common Mistakes

1. Conjugating πρέπει to match the subject. There is no ×πρέπω or ×πρέπουμε — πρέπει is fixed for everyone.

❌ Πρέπουμε να φύγουμε νωρίς αύριο.

Incorrect — πρέπει never conjugates; the person lives on the να-verb.

✅ Πρέπει να φύγουμε νωρίς αύριο.

prépi na fíghume norís ávrio

We have to leave early tomorrow.

2. Using personal μπορώ for impersonal possibility. "It might rain" is μπορεί (frozen), not μπορώ ("I can").

❌ Μπορώ να βρέξει το βράδυ.

Incorrect — impersonal possibility uses the frozen μπορεί, not the first-person μπορώ.

✅ Μπορεί να βρέξει το βράδυ.

borí na vréksi to vrádhi

It might rain tonight.

3. Dropping the να. Unlike English "must go," Greek always needs the linking να: πρέπει να φύγω.

❌ Πρέπει φύγω αμέσως.

Incorrect — πρέπει must be followed by να before the verb.

✅ Πρέπει να φύγω αμέσως.

prépi na fígho amésos

I have to leave right away.

4. Conjugating the past έπρεπε. The past of πρέπει is invariable έπρεπε for all persons — no ×έπρεπα.

❌ Έπρεπα να σε είχα ακούσει.

Incorrect — the past is the invariable έπρεπε, whatever the person.

✅ Έπρεπε να σε είχα ακούσει.

éprepe na se ícha akúsi

I should have listened to you.

Key Takeaways

πρέπει να (obligation) and μπορεί να (possibility) are impersonal and invariable — the person is shown by the να-verb, not by the modal.
Don't confuse frozen μπορεί ("it may") with the conjugating personal μπορώ / μπορείς ("I / you can") — same word family, different jobs.
Negation: δεν πρέπει να = "must not"; μπορεί να μην = "might not" (weak) vs δεν μπορεί να = "it can't be that" (strong).
Past: έπρεπε να (invariable) = "had to / should have"; μπορεί να
- past = "may have"; μπορούσε να = "could have."

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