Masculine Nouns in -ης and -ες

This masculine class is defined by a pair of endings: -ης in the singular, -ες in the plural. It is full of high-frequency human nouns — ο μαθητής (the student/pupil), ο ναύτης (the sailor), ο πολίτης (the citizen), ο εργάτης (the worker), ο κλέφτης (the thief) — plus a huge number of Greek family names (Παπαδάκης, Θεοδωράκης). The endings are tidy and regular; the two things to watch are the accent on the genitive plural and a look-alike adjective that declines nothing like these nouns.

The full paradigm

Take ο μαθητής ("the student"), an oxytone noun stressed on the final syllable:

The endings are -ης / -η / -η / -η in the singular and -ες / -ών / -ες / -ες in the plural. As with every masculine class, the -ς only marks the nominative singular (μαθητής); the genitive, accusative and vocative singular are all the bare -η (μαθητή). Three of the four singular forms are therefore identical — a mercy for the learner.

Accent: oxytone agents versus paroxytone nouns

Two accent types share this ending. Many are oxytone agent nouns in -τής — ο μαθητής, ο πωλητής (salesperson), ο αθλητής (athlete) — with the stress locked on the last syllable. Others are paroxytone, stressed on the next-to-last syllable: ο ναύτης, ο πολίτης, ο εργάτης, ο κλέφτης.

Where the difference bites is the genitive plural, which is regularly oxytone -ών for this whole class — even for the paroxytone nouns, whose accent therefore jumps to the ending:

• ο ναύτης → των ναυτών (not ×των ναύτων)
• ο εργάτης → των εργατών
• ο πολίτης → των πολιτών

For the already-oxytone μαθητής this is invisible (μαθητών keeps the stress on the end anyway), but for ναύτης and its kind the shift is real and audible.

Family names in -ης

A large share of Greek surnames end in -ης — Παπαδάκης, Θεοδωράκης, Καζαντζάκης — and in the singular they decline exactly like μαθητής: του Παπαδάκη (of Papadakis), τον Παπαδάκη (I saw Papadakis). But when you mean the whole family ("the Papadakis family / the Papadakises"), Greek uses a special imparisyllabic plural in -ηδες:

So the plurals part ways by meaning: οι μαθητές (students, the common noun) but οι Παπαδάκηδες (the members of one family). Don't extend the family-style -ηδες plural to ordinary nouns.

The vocative in -η

To address a masculine -ης noun, use the bare -η — the same form as the genitive and accusative singular:

First names follow the same rule: Γιάννης → Γιάννη, Δημήτρης → Δημήτρη, Χρήστος… — no, that last one is a -ος name (Χρήστο). Keep to the ending: any masculine noun or name in -ης is addressed with -η.

Do not confuse the noun -ης with the adjective -ης

Here is the pitfall that even intermediate learners fall into. Greek also has a family of two-termination adjectives ending in -ης in the masculine and feminine and -ές in the neuter: διεθνής (international), ακριβής (precise), συνεχής (continuous), διεθνής/διεθνής/διεθνές. These look like our nouns in the nominative, but they descend from the Ancient Greek third declension and decline completely differently — their genitive is in -ούς, not -η:

• Noun: ο μαθητής → του μαθητή
• Adjective: ο διεθνής (αγώνας) → του διεθνούς (αγώνα)

So a "student's" is του μαθητή, but "of the international (match)" is του διεθνούς. Never decline the adjective as if it were a μαθητής-noun. The full adjective pattern is on Two-termination adjectives in -ης/-ης/-ές.

Common Mistakes

1. Keeping the -ς in the oblique singular. Genitive, accusative and vocative all use the bare -η.

2. Leaving the genitive plural stress in place. Paroxytone nouns move the accent to -ών.

3. Giving a common noun the -ηδες family plural. μαθητής is parisyllabic; its plural is μαθητές.

4. Declining the adjective -ής like the noun. διεθνής is an adjective with genitive διεθνούς.

Key Takeaways

• The class is singular -ης / plural -ες: endings -ης / -η / -η / -η (sg.) and -ες / -ών / -ες / -ες (pl.).
• The -ς marks only the nominative singular; genitive, accusative and vocative singular are the bare -η (μαθητή).
• The genitive plural is oxytone -ών for the whole class, so paroxytone nouns shift their accent: ναύτης → των ναυτών.
• Vocative singular is -η (Γιάννη!, μαθητή!).
• Family names in -ης decline like the nouns in the singular but take a special -ηδες plural for "the whole family" (οι Παπαδάκηδες).
• Don't confuse this noun ending with the two-termination adjective in -ης (διεθνής), whose genitive is -ούς (διεθνούς).