ξεχνάω/ξεχνώ (to forget) | Greek Grammar

English splits this verb's work three ways. You forget a name, you forget to post a letter, and when the thing is a phone on the back seat of a taxi you switch verbs entirely and leave it. Greek does all three with ξεχνάω and changes nothing but the complement — which makes the third one, the leave-behind reading, the sentence learners never produce on their own.

Principal parts

Slot	Forms	Note
Present	ξεχνάω/ξεχνώ, ξεχνάς, ξεχνάει/ξεχνά, ξεχνάμε, ξεχνάτε, ξεχνάνε/ξεχνούν	-άω (informal) beside -ώ (formal)
Imperfect	ξεχνούσα
Aorist	ξέχασα, ξέχασες, ξεχάσαμε	ν gone, -ασ- linking vowel
Dependent (θα, να)	ξεχάσω
Imperative	ξέχνα / ξεχνάτε · ξέχασε / ξεχάστε	the pair matters — see below
Perfect	έχω ξεχάσει
Gerund	ξεχνώντας	no active participle beyond this
Mediopassive	ξεχνιέμαι, aorist ξεχάστηκα	two distinct jobs — see below
Participle	ξεχασμένος, -η, -ο	forgotten; abandoned

ξέχασα is not an irregular form to be memorised on its own. ξεχνάω belongs to the small -νάω group that drops its ν in the perfective and takes -ασ- — περνάω/πέρασα, κερνάω/κέρασα, γερνάω/γέρασα — which is laid out with the rest of them on irregular Class Β verbs. Knowing the group is what stops ×ξεχνήσα. The learned synonym λησμονώ (formal, literary) is alive in written Greek and in the fixed αλησμόνητος ("unforgettable").

Government

Frame	Example	Reading
bare accusative	Ξέχασα το όνομά του.	a fact, a name, a language
να dependent	Ξέχασα να τον πάρω.	something you failed to do
ότι / πως clause	Ξεχνάς ότι δουλεύω αύριο.	a forgotten fact, spelled out
accusative + place	Ξέχασα τα κλειδιά στο γραφείο.	left it behind — English changes verb
genitive clitic + accusative	Μου ξέχασες το ψωμί.	whose loss it is

Ξέχασα τον κωδικό και πρέπει να τον ζητήσω πάλι από την τράπεζα.

kséchasa ton kodhikó ke prépi na ton zitíso páli apó tin trápeza

I've forgotten the PIN and I'll have to ask the bank for it again.

Ξέχασα να βγάλω τα σκουπίδια και τώρα μυρίζει όλη η κουζίνα.

kséchasa na vghálo ta skupídhia ke tóra mirízi óli i kuzína

I forgot to take the rubbish out and now the whole kitchen smells.

Ξέχασα τη ζακέτα μου στο εστιατόριο και γύρισα τρέχοντας να τη βρω.

kséchasa ti zakéta mu sto estiatório ke yírisa tréchondas na ti vro

I left my cardigan at the restaurant and ran back to find it.

💡

Do not reach for αφήνω in that third sentence. άφησα το κινητό στο ταξί says you put it there on purpose. The whole point of ξέχασα is that the leaving was an oversight — Greek marks the intention in the verb, where English marks it nowhere and lets the context do the work.

The για you expect from English forget about is not available for the thing forgotten. A για phrase after this verb can only measure time: Ξέχασα για λίγο ότι είχαμε καλεσμένους ("For a moment I forgot we had guests"). The thing itself is a bare accusative, always.

Whose loss it is

The genitive clitic in Μου ξέχασες το ψωμί does not mean "you forgot me". It names the person the oversight lands on — the same construction as Μου έφυγε το τρένο, worked out on genitive clitics. It is everywhere in domestic Greek and it carries a mild reproach (informal).

Πάλι μου ξέχασες το ψωμί, τι θα φάμε το βράδυ;

páli mu kséchases to psomí, ti tha fáme to vrádhi;

You've forgotten my bread again — what are we going to eat tonight?

The two imperatives

Ξέχνα το, δεν αξίζει να στεναχωριέσαι άλλο γι' αυτόν.

kséchna to, dhen aksízi na stenachoriése álo y' aftón

Let it go — he isn't worth being upset over any more.

Ξέχασέ το — μας απέρριψαν την αίτηση για δεύτερη φορά.

kséchasé to — mas apéripsan tin étisi ya dhéfteri forá

Forget it — they turned our application down for a second time.

Both are everyday and both come out as forget it; the aspect tilts them rather than splitting them in two. Imperfective Ξέχνα το asks for an ongoing letting-go — stop dwelling on it, day by day. Perfective Ξέχασέ το packages it as one decision, whether that decision is put it out of your mind or write it off, it isn't happening. Note the second accent on the host, ξέχασέ το: a proparoxytone verb takes one when a clitic attaches, and that is the perfective imperative pattern generally.

ξεχνιέμαι does two unrelated things

Form	Job
3rd person, of a skill or an event	is (never) forgotten
1st / 2nd person	get absorbed, lose track of yourself

Το ποδήλατο δεν ξεχνιέται, όσα χρόνια κι αν περάσουν.

to podhílato dhen ksechniéte, ósa chrónia ki an perásun

You never forget how to ride a bike, however many years go by.

Ξεχάστηκα στη συζήτηση και δεν πήρα το φάρμακό μου.

ksechástika sti sizítisi ke dhen píra to fármakó mu

I got so caught up in the conversation that I didn't take my medicine.

ξεχασμένος covers both the thing mislaid and the person abandoned, which is why ξεχασμένος κι από τον Θεό is said of a village nobody has looked after for thirty years.

Βρήκα ένα ξεχασμένο μπουκάλι κρασί στο πίσω ράφι.

vríka éna ksechazméno bukáli krasí sto píso ráfi

I found a forgotten bottle of wine at the back of the shelf.

The other half of the pair is θυμάμαι, which is deponent and behaves nothing like this verb.

Set phrases

Phrase	Meaning
Μην ξεχάσεις!	Don't forget! — ν kept before ξ
Το ξέχασα τελείως.	It went completely out of my head.
περασμένα, ξεχασμένα	let bygones be bygones
ξεχασμένος κι από τον Θεό	God-forsaken
τον ξέχασε ο Χάρος	said of somebody living to a great age (informal)
Να μη με ξεχνάς.	Don't be a stranger.

Μην ξεχάσετε τα διαβατήρια, χωρίς αυτά δεν μπαίνουμε στο πλοίο.

min ksechásete ta dhiavatíria, chorís aftá dhen bénume sto plío

Don't forget the passports — without them we're not getting on the boat.

Key Takeaways

ξεχνάω · ξεχνούσα · ξέχασα · ξεχάσω · ξέχνα / ξεχάστε · έχω ξεχάσει · ξεχασμένος.
The aorist drops the ν and takes -ασ- with περνάω, κερνάω, γερνάω. ×ξεχνήσα does not exist.
Three readings, one verb: a fact (accusative), an action (να), and an object left behind where English says left.
Ξέχνα το and Ξέχασέ το both mean forget it: the imperfective keeps you letting go, the perfective makes it one decision.
ξεχνιέμαι is is forgotten in the third person and lose track of yourself in the first.

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