Questions of Greek Grammar

...and these four are isosyllabic, but the fifth is imparisyllabic literally: "having unequal syllables", and it exists in the three genders, meaning all nouns declined with unequal syllables, whose genitive ends in -ος, the dative ends in -ι, and the accusative ends in -α.

ὁ αἴας Aias/Ajax, τοῦ αἴαντος, τῷ αἴαντι, τὸν αἴαντα, ὦ αἴαν, and ὁ αἴας. τὰ αἴαντε, τοῖν αἰάντοιν, ὦ αἴαντε. οἱ αἴαντες, τῶν αἰάντων, τοῖς αἴασι, τοὺς αἴαντας, ὦ αἴαντες.

ὁ θόας Thoas, τοῦ θόαντος. Those ending in -ας, which are masculine, disyllabic, barytone having no accent on the final syllable, ending in a long syllable, and possessing a -ντ-, are declined like the above.

ὁ λάχης Laches, τοῦ λάχητος. ὁ κέβης Cebes, τοῦ κέβητος. Those ending in -ης that are iambic and do not possess a τ before the -ης, make the genitive in -τος.

ὁ πάρις Paris, τοῦ πάριδος, τῷ πάριδι, τὸν πάριδα and πάριν, the vocative, ὦ πάρι.

ὁ ἄδωνις Adonis, τοῦ ἀδώνιδος. Those ending in -ις that are proper nouns are declined via -δος, like the above. Ionically, however, they are without the δ, such as πάριος, ἀδώνιος.

ὁ βόθυς pit, τοῦ βόθυνος. ὁ ἡδὺς sweet, τοῦ ἡδέος. Those ending in -υς: those that have three genders, such as ἡδὺς, ἡδεῖα, ἡδὺ, are declined via -εος. Those that are monogenetic are declined via -υος, except for πῆχυς forearm, πήχεως; πέλεκυς axe, πελέκεως; ἔγχελυς eel, ἐγχέλεως, which are declined in the Attic manner via the long ω.

ὁ ἱδρὼς sweat, τοῦ ἱδρῶτος; ὁ γέλως laughter, τοῦ γέλωτος; ὁ ἥρως hero, τοῦ ἥρωος. For those ending in -ως, which are masculine and barytone: those that are preceded by a short syllable are declined via -τος; those preceded by a long syllable are declined via a pure -ος.