Adjectives in -ος / -α / -ο

Greek's biggest adjective class ends in -ος for the masculine, and it splits into two feminines: most adjectives take (καλός → καλή), but a large subgroup takes (ωραίος → ωραία). This page is only about the subgroup. The masculine (-ος) and neuter (-ο) columns are identical to the ordinary καλός / καλή / καλό type — so if you already know that one, the only new thing here is the feminine, and one rule tells you when it applies.

The rule: -α after a vowel

Look at the letter right before the ending. If the stem ends in a vowel, the feminine is ; otherwise it is the default .

MasculineFeminineWhy
ωραίοςωραίαstem ends in -αι- (vowel)
νέοςνέαstem ends in -ε- (vowel)
κρύοςκρύαstem ends in -υ- (vowel)
πλούσιοςπλούσιαstem ends in -ι- (vowel)
but καλόςκαλήstem ends in -λ- (consonant)

The everyday members of the -α group are worth memorising as a set: ωραίος (nice, lovely), νέος (new, young), κρύος (cold), παλιός (old), πλούσιος (rich), γαλάζιος (light blue), τέλειος (perfect), ίσιος (straight), άδειος (empty), όποιος (whichever). They all share the same trigger: a vowel sits in front of the ending.

Τι ωραίος καιρός σήμερα, πάμε μια βόλτα;

ti oréos kerós símera, páme mia vólta;

What lovely weather today — shall we go for a walk?

Η Αθήνα είναι πιο ωραία την άνοιξη παρά το καλοκαίρι.

i Athína íne pio oréa tin ániksi pará to kalokéri

Athens is nicer in spring than in summer.

Βρήκαμε ένα ωραίο σπίτι κοντά στη θάλασσα.

vríkame éna oréo spíti kondá sti thálasa

We found a nice house near the sea.

The full paradigm

Here is ωραίος across all three genders. Notice that only the feminine column differs from the καλός type — the masculine and neuter are exactly the standard -ος endings.

MasculineFeminineNeuter
Nom. sg.ωραίοςωραίαωραίο
Gen. sg.ωραίουωραίαςωραίου
Acc. sg.ωραίοωραίαωραίο
Nom. pl.ωραίοιωραίεςωραία
Gen. pl.ωραίωνωραίωνωραίων
Acc. pl.ωραίουςωραίεςωραία

The key consequence: because the feminine is , it declines like an -α noun — genitive singular -ας (ωραίας), plural -ες (ωραίες). That is the real difference from καλή, whose feminine follows the -η pattern (καλής, καλές). One vowel at the stem's edge changes the whole feminine sub-declension.

Ο νέος διευθυντής είναι αυστηρός αλλά δίκαιος.

o néos dhiefthindís íne afstirós alá dhíkeos

The new manager is strict but fair.

Έχεις τη νέα διεύθυνσή μου ή να σου τη στείλω;

éches ti néa dhiéfthinsí mu i na su ti stílo;

Do you have my new address, or should I send it to you?

Αγόρασα ένα νέο τηλέφωνο γιατί το παλιό κόλλαγε συνέχεια.

aghórasa éna néo tiléfono yatí to palió kólaye sinéchia

I bought a new phone because the old one kept freezing.

ωραία = ωραία: the same-spelling trap

Read this off the paradigm carefully. The feminine singular and the neuter plural are spelled and pronounced identically: both are ωραία. So a bare ωραία is ambiguous until you see its noun (or article):

  • η ωραία μέρα — the lovely day (feminine singular)
  • τα ωραία πράγματα — the lovely things (neuter plural)

This is not a quirk of ωραίος; it holds for every adjective in this class — νέα, κρύα, πλούσια, τέλεια all double as feminine singular and neuter plural. The article and the noun's ending resolve it every time, so it never causes real confusion in a sentence — but it does trip up learners who try to make the adjective agree with the wrong number.

Ήταν μια ωραία μέρα και καθίσαμε έξω για καφέ.

ítan mia oréa méra ke kathísame ékso ya kafé

It was a lovely day and we sat outside for coffee.

Τα παιδιά είπαν πολλά ωραία λόγια για τον δάσκαλό τους.

ta pedhiá ípan polá oréa lóya ya ton dháskaló tus

The children said many nice things about their teacher.

Ο ουρανός ήταν καθαρός και η θέα από ψηλά ήταν τέλεια.

o uranós ítan katharós ke i théa apó psilá ítan télia

The sky was clear and the view from up high was perfect.

Accent

These adjectives obey the same three-syllable accent rule as every -ος word: a stress sitting three syllables back cannot survive in front of the "heavy" genitive endings and slides forward. In practice, though, almost none of the common -α adjectives are affected — words like ωραίος, νέος, κρύος and πλούσιος carry their stress on the next-to-last syllable (and the -ιος ending collapses into one glide syllable, plú-sios), so nothing moves anywhere in the paradigm. You can treat them as fixed-stress and not worry about it.

Το φαγητό στο χωριό είναι απλό αλλά πεντανόστιμο.

to fayitó sto chorió íne apló alá pendanóstimo

The food in the village is simple but delicious.

Common Mistakes

1. Giving a vowel-stem adjective the default -η feminine. English speakers latch onto the καλή pattern and over-apply it. After a vowel it has to be -α.

❌ Ήταν μια νέη ιδέα.

Incorrect — νέος has a vowel stem, so the feminine is νέα, not ×νέη.

✅ Ήταν μια νέα ιδέα.

ítan mia néa idhéa

It was a new idea.

2. Using the -ης genitive on the -α feminine. Because the feminine is -α, its genitive singular is -ας, exactly like an -α noun — not the -ης of the καλή type.

❌ Το χρώμα της ωραίης μέρας.

Incorrect — the -α feminine takes genitive -ας: της ωραίας.

✅ Το χρώμα της ωραίας μέρας.

to chróma tis oréas méras

The colour of the lovely day.

3. Using -ες for the neuter plural. The neuter plural is (ωραία, νέα); -ες is the feminine plural (ωραίες, νέες). Learners see the feminine singular ωραία, assume the plural is ωραίες, and wrongly attach it to a neuter noun.

❌ Είδαμε ωραίες τοπία στον δρόμο.

Incorrect — τοπία is neuter plural, so the adjective is ωραία, not the feminine ωραίες.

✅ Είδαμε ωραία τοπία στον δρόμο.

ídhame oréa topía ston dhrómo

We saw beautiful landscapes on the way.

4. Treating the -α feminine as invariable across number. The feminine singular ωραία does change in the plural — to ωραίες. It is not frozen the way the neuter plural ωραία looks frozen next to the feminine singular.

❌ Οι μέρες στη Σαντορίνη ήταν ωραία.

Incorrect — a plural feminine subject needs the plural ωραίες.

✅ Οι μέρες στη Σαντορίνη ήταν ωραίες.

i méres sti Sandoríni ítan orées

The days in Santorini were lovely.

💡
Not every vowel-stem adjective plays along perfectly: a handful of -αιος words take -η in the modern standard (βέβαιος → βέβαιη, δίκαιος → δίκαιη), and a couple of consonant-stem colour words take -α by tradition (γκρίζος → γκρίζα). These are lexical exceptions to memorise — but the productive rule (vowel in front of -ος → feminine -α) covers the everyday adjectives you actually reach for.

Key Takeaways

  • The masculine (-ος) and neuter (-ο) forms are identical to the καλός type; only the feminine differs.
  • Feminine appears when the stem ends in a vowel: ωραία, νέα, κρύα, παλιά, πλούσια, τέλεια.
  • The -α feminine declines like an -α noun — genitive singular -ας, plural -ες (ωραίας, ωραίες).
  • Feminine singular and neuter plural share one spelling: ωραία = the lovely day and the lovely things — the article and noun disambiguate.
  • Watch two lexical exceptions: some -αιος adjectives go -η (βέβαιη, δίκαιη); γκρίζος goes -α.

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Related Topics

  • Adjectives in -ος / -η / -οA1The full paradigm of the largest and most regular Greek adjective class — καλός, μικρός, ψηλός, όμορφος — declined across all four cases, both numbers and all three genders, with the useful shortcut that each gender copies a noun declension you already know, plus the vocative -ε and why these adjectives keep their accent fixed where the matching nouns shift it.
  • Adjective AgreementA1The one reflex every Greek adjective demands — copy the noun's gender, number and case onto the adjective, in the attributive slot (ο μεγάλος κήπος → του μεγάλου κήπου) and in the predicative slot after είμαι (το σπίτι είναι μεγάλο) alike — and the two English-speaker errors, leaving the adjective bare and agreeing in gender but not case.
  • Feminine Nouns in -αA1The most common feminine pattern — η γυναίκα, η ώρα, η μέρα, η θάλασσα — with its plain paradigm, the -ας genitive singular, and the one tricky cell: the accent-shifting genitive plural (η θάλασσα → των θαλασσών).
  • Accent Shift in DeclensionB1Why the stress jumps forward when you decline a noun — άνθρωπος but του ανθρώπου, αυτοκίνητο but του αυτοκινήτου, κυβέρνηση but των κυβερνήσεων. The three-syllable law applied systematically, gender by gender, with tables showing exactly which cells move.
  • How Greek Adjectives WorkA1The map of the Greek adjective system — a describing word that agrees with its noun in gender, case and number and declines just like a noun, the dominant καλός/καλή/καλό pattern, the smaller classes it fans out into, and why an English speaker has to start inflecting a word that in English never changes at all.