Accent in Adjective Declension

Nouns make you work: decline ο άνθρωπος and the accent jumps forward to του ανθρώπου; the accent shift in declension is one of the fiddlier things about the Greek noun. Adjectives, happily, are the easy case. The overwhelming majority of Greek adjectives keep their accent fixed on the same syllable through the whole paradigm — no jumping, no forward slide. This page explains why that is, works through the few places where care is genuinely needed, and gives you the one contrast with nouns that trips up even advanced learners.

The default: -ος / -η / -ο adjectives don't move

Take όμορφος ("beautiful"), stressed on its third-from-last syllable (ό-μορ-φος). Run it through every case and both numbers and the accent never leaves that ό:

Now put it beside the noun. The matching masculine noun ο άνθρωπος shifts to του ανθρώπου in the genitive; the adjective, in the same slot, stays put: του όμορφου, never του ομόρφου.

Look closely at that second sentence: the adjective όμορφων keeps its accent on ό, while the noun σπιτιών carries its accent out to the ending. One phrase, two different behaviours — and that is the whole lesson.

Why the noun moves but the adjective doesn't

Both words end up in a form that would be perfectly legal either way — ανθρώπου and όμορφου each keep the accent inside the last three syllables, so the three-syllable law is not what is forcing the noun forward. The real driver is history. The genitive endings -ου / -ων were "heavy" in Ancient Greek and pulled a proparoxytone's accent forward, and the nouns carried that inherited behaviour down into the modern language. Demotic adjectives levelled it out: they generalised a single, fixed accent across the paradigm because it is simpler. So the shift is not a phonological rule Greek still enforces — it is a lexical inheritance that nouns kept and everyday adjectives dropped. That is exactly why όμορφος stays όμορφου while άνθρωπος becomes ανθρώπου.

Here έμπειρος (proparoxytone) keeps its accent on έ through the genitive — του έμπειρου, not του εμπείρου — while the noun γιατρός carries its accent on the ending as it always does.

Oxytone adjectives: the accent is glued to the ending

The other big group is the oxytone adjectives — καλός, μικρός, ψηλός, ακριβός, φθηνός, ζωντανός — stressed on the last syllable. Their accent is welded to the ending, so wherever the ending goes, the accent goes with it, and there is never any question of a shift.

So between the fixed-accent proparoxytones (όμορφος → όμορφου) and the end-stressed oxytones (καλός → καλού), the two commonest adjective classes give you nothing to worry about. This is the payoff worth remembering: for the ordinary -ος / -η / -ο adjective, and its sibling -ος / -α / -ο, you can treat the accent as stable and simply swap endings.

The -ύς / -ιά / -ύ class

Adjectives like βαθύς (deep), φαρδύς (wide), βαρύς (heavy) are oxytone throughout, so their accent likewise stays on the ending in every form — masculine βαθύς, feminine βαθιά, neuter βαθύ, genitive βαθιού / βαθιάς, and the plural genitive βαθιών.

The learned -ής / -ές class: here the ending does carry the stress

The one class where an accent genuinely rides out to the ending in the genitive is the learned two-ending adjectives in -ής / -ές — διεθνής (international), ακριβής (exact), συνεχής (continuous), ευγενής (noble). These descend directly from the ancient consonant-stem declension, and their genitive endings — singular -ούς, plural -ών — are stressed. So beside nominative διεθνής you get genitive singular διεθνούς and genitive plural διεθνών, all carrying the accent on the ending. This is formal, written register, but you will meet it constantly in the press and in academic prose.

The formal doublets: του άγιου vs του Αγίου

A few adjectives live in two registers at once, and the accent tells them apart. The everyday adjective keeps its accent fixed, demotic-style; the frozen, learned use retains the ancient shifted genitive. The cleanest example is άγιος ("holy, saintly"). Used as a plain adjective it behaves like όμορφος and keeps its accent home; used as a religious title, it shifts.

The same split runs through a small set of learned proparoxytone adjectives whose shifted genitive survives in formal, frozen phrasing: έντιμος ("honest") keeps its accent home as an ordinary adjective (του έντιμου δικαστή, "the honest judge") but you will see του εντίμου in ceremonial or legal set phrases. Treat the shifted form as a register marker, not the default: in living speech and ordinary writing these adjectives keep the accent fixed.

Common Mistakes

1. Shifting an -ος adjective like a noun. This is the big one — the noun του ανθρώπου lures learners into ×του ομόρφου, ×του εξύπνου. The adjective keeps its accent home.

2. Freezing the noun while correctly keeping the adjective fixed. In του νέου ανθρώπου, the adjective stays home (νέου) but the noun still shifts (ανθρώπου). Don't let the fixed adjective talk you out of the noun's shift.

3. Mis-forming the learned -ής genitive. The genitive of διεθνής is διεθνούς, not the nominative form.

4. Reaching for the shifted form where the everyday one fits. Both accents exist — άγιου is the demotic default, αγίου the formal/ecclesiastical variant (and the one locked into titles like του Αγίου Νικολάου). Neither is wrong; the slip is register, not grammar. For an ordinary "saintly teacher" the everyday άγιου is what a speaker reaches for, and the shifted αγίου would sound church-flavoured.

Key Takeaways

• The everyday adjective keeps its accent fixed through the whole paradigm — όμορφος → του όμορφου, των όμορφων — unlike the matching noun (άνθρωπος → του ανθρώπου). This is the single most useful fact on the page.
• The shift the noun undergoes is a historical inheritance (heavy genitive endings) that demotic adjectives levelled away; it is not a live phonological rule, which is why the two behave differently in identical slots.
• Oxytone adjectives (καλός, φθηνός, ζωντανός) and the -ύς / -ιά / -ύ class (βαθύς) keep the accent on the ending throughout — again, no shift to track.
• The learned -ής / -ές class is the one place the accent genuinely rides the ending in the genitive: διεθνής → διεθνούς → διεθνών (formal register).
• A few adjectives form register doublets: demotic keeps the accent home (του άγιου, του έντιμου), formal/frozen usage keeps the ancient shift (του Αγίου, του εντίμου).