A small but very useful class of adjectives ends in -ύς (masculine), -ιά (feminine), -ύ (neuter). It is a closed set — you cannot make new ones — but the members you already need every day: βαθύς (deep), βαρύς (heavy), πλατύς (wide, broad), φαρδύς (wide, of clothes), μακρύς (long), παχύς (thick, fat). They cluster around one meaning-field — the physical dimensions and textures of things — which is exactly why they come up so often. The declension looks irregular at first, but it is completely regular within the class, and the whole trick is spotting where the -υ- turns into an -ι-.
The shape of the class
Take βαθύς ("deep"). Here is the full paradigm.
| Masculine | Feminine | Neuter | |
|---|---|---|---|
| Nom. sg. | βαθύς | βαθιά | βαθύ |
| Gen. sg. | βαθιού | βαθιάς | βαθιού |
| Acc. sg. | βαθύ | βαθιά | βαθύ |
| Nom. pl. | βαθιοί | βαθιές | βαθιά |
| Gen. pl. | βαθιών | βαθιών | βαθιών |
| Acc. pl. | βαθιούς | βαθιές | βαθιά |
Here is the pattern in one sentence: the bare -ύ (with its nominative -ς) survives in only three cells — masculine nominative βαθύς, and the neuter singular βαθύ together with the masculine accusative singular, also βαθύ. Everywhere else the stem becomes βαθι- and picks up ordinary endings: feminine -ά, -άς, -ές; masculine plural -οί, -ούς; genitive -ού, -ών. So the feminine and the whole plural look and behave like a stem ending in -ι.
Το ποτάμι εδώ είναι πιο βαθύ απ' ό,τι φαίνεται, μην μπεις.
to potámi edhó íne pio vathí ap' óti fénete, min bis
The river here is deeper than it looks — don't go in.
Πάρε μια βαθιά ανάσα πριν αρχίσεις να μιλάς.
páre mia vathyá anása prin archísis na milás
Take a deep breath before you start speaking.
Οι βαθιές πληγές θέλουν χρόνο για να κλείσουν.
i vathyés pliyés thélun chróno ya na klísun
Deep wounds take time to close.
Synizesis: -ιά is one syllable
The single most important thing to get right about this class is the sound of the feminine and plural forms. The -ιά in βαθιά is not two syllables (va-thi-á) — the ι collapses into a consonantal glide [j] and the ending is a single syllable: βαθιά = va-thyá. The same synizesis runs through the whole -ι- part of the paradigm: βαθιού = va-thyú, βαθιοί = va-thyí, βαθιές = va-thyés. The stress always lands on that final syllable.
Get this wrong and you sound like you are reading Ancient Greek out loud. Two syllables (va-thi-á) is how a textbook prints it; one syllable (vathyá) is how every Greek says it.
Αυτός ο καφές είναι πολύ βαρύς για μένα το βράδυ.
aftós o kafés íne polí varís ya ména to vrádhi
This coffee is too strong for me in the evening.
Κουβαλάει μια βαριά τσάντα με βιβλία κάθε μέρα.
kuvalái mia varyá tsánda me vivlía káthe méra
She carries a heavy bag of books every day.
Το τραπέζι είναι πολύ βαρύ, δεν το σηκώνω μόνος μου.
to trapézi íne polí varí, dhen to sikóno mónos mu
The table is too heavy — I can't lift it on my own.
More members, and one that only looks like one
The everyday members behave exactly like βαθύς. A few useful ones in context:
Φόρεσε ένα φαρδύ παντελόνι για να είναι άνετος στο ταξίδι.
fórese éna fardhí pandelóni ya na íne ánetos sto taksídhi
He wore loose trousers to be comfortable on the trip.
Ο δρόμος εδώ είναι πλατύς, χωράνε άνετα δύο λεωφορεία.
o dhrómos edhó íne platís, choráne áneta dhío leoforía
The road here is wide — two buses fit easily.
Είχε μακριά μαλλιά όταν την πρωτογνώρισα.
íche makryá malyá ótan tin protoghnórisa
She had long hair when I first met her.
Two watch-outs on membership. First, μακριά ("long", the neuter plural / feminine here) is spelled and pronounced exactly like the common adverb μακριά ("far away") — context tells them apart. Second, γλυκός ("sweet") is not a member: its masculine is the ordinary -ός (γλυκός, not ×γλυκύς) and its neuter is -ό (γλυκό). But — and this is the catch — its feminine borrows this class's ending: γλυκιά, with the same synizesis. So γλυκός sits with a foot in each camp: -ός/-ό masculine and neuter, -ιά feminine.
Ήπιαμε έναν γλυκό καφέ και φάγαμε ένα γλυκό στην πλατεία.
ípiame énan ghlikó kafé ke fághame éna ghlikó stin platía
We had a sweet coffee and ate a dessert in the square.
Τι γλυκιά που είναι η κόρη σου, σου μοιάζει πολύ.
ti ghlikyá pu íne i kóri su, su miázi polí
What a sweet girl your daughter is — she really looks like you.
The learned feminine in -εία
A few adjectives of this shape are ancient words that survive mainly in formal, scientific or fixed usage, and their feminine keeps the learned ending -εία instead of -ιά. This is a matter of register, not a mistake — both forms are correct Greek, but they live in different places.
Η γιατρός εξήγησε ότι η φλεγμονή είναι σε οξεία φάση.
i yatrós eksíyise óti i fleghmoní íne se oksía fási
The doctor explained that the inflammation is in an acute phase.
Χάραξε μια ευθεία γραμμή με τον χάρακα.
chárakse mia efthía ghramí me ton cháraka
Draw a straight line with the ruler.
Common Mistakes
1. Giving the feminine the default -η. The feminine of this class is -ιά, never -η. Learners reach for the καλή pattern by reflex.
❌ Ήταν μια βαθή συζήτηση για τη ζωή.
Incorrect — the feminine of βαθύς is βαθιά, not ×βαθή.
✅ Ήταν μια βαθιά συζήτηση για τη ζωή.
ítan mia vathyá sizítisi ya ti zoí
It was a deep conversation about life.
2. Keeping -ς on the neuter singular. The neuter is bare -ύ (βαθύ); the -ς belongs only to the masculine nominative (βαθύς).
❌ Το πηγάδι είναι πολύ βαθύς.
Incorrect — a neuter noun (το πηγάδι) needs the neuter βαθύ, without -ς.
✅ Το πηγάδι είναι πολύ βαθύ.
to pighádhi íne polí vathí
The well is very deep.
3. Forming the masculine plural like an -ος adjective. The masculine plural is -ιοί (βαθιοί), not ×βαθύοι or ×βαθοί.
❌ Οι βαθύοι δεσμοί δεν σπάνε εύκολα.
Incorrect — the masculine plural is βαθιοί.
✅ Οι βαθιοί δεσμοί δεν σπάνε εύκολα.
i vathyí dhezmí dhen spáne éfkola
Deep bonds don't break easily.
4. Pronouncing -ιά as two syllables. va-thi-á with three beats is not how the word sounds; the ι is a glide and the ending is one syllable, va-thyá. This is a pronunciation error more than a spelling one, but it marks you out instantly.
✅ Ο ουρανός είχε ένα βαθύ μπλε χρώμα το σούρουπο.
o uranós íche éna vathí ble chróma to súrupo
The sky was a deep blue at dusk.
Key Takeaways
- A closed, high-frequency class of physical-quality adjectives: βαθύς, βαρύς, πλατύς, φαρδύς, μακρύς, παχύς.
- The bare -ύ survives only in masculine nominative (-ύς) and the neuter/masculine-accusative singular (-ύ); everywhere else the stem is -ι- with ordinary endings.
- Feminine -ιά, masculine plural -ιοί, feminine plural -ιές, neuter plural -ιά — all with synizesis: -ιά is one syllable (vathyá).
- γλυκός is -ός/-ό but borrows the -ιά feminine (γλυκιά).
- The learned feminine -εία (οξεία, ευθεία, βαρεία) is a formal/technical register, not an error — reserve it for fixed phrases.
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Start learning Greek →Related Topics
- Adjectives in -ος / -η / -οA1 — The 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.
- Elision and SynizesisB1 — Why σε αυτό becomes σ' αυτό, από εδώ becomes απ' εδώ, and θα έρθω becomes θα 'ρθω — and why μια is one syllable ('mya'), not two. The vowel-smoothing that makes spoken Greek flow; full forms sound stiff.
- Accent Shift in DeclensionB1 — Why 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.
- Adjective AgreementA1 — The 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.