Accent and declension patterns of adjectives ending in -υς (masculine and feminine), stress shifts, examples (ἠΰς, ἡδύς, ταχύς, θῆλυς, ἥμισυς), and related feminine nouns and place/ethnic names
Τὰ εἰς 'υς' ἁπλᾶ ἐπιθετικὰ διὰ τοῦ 'ε' κλινόμενα τριγενῆ δισύλλαβα ὄντα ὀξύνεται, ἠΰς, ἡδύς, ταχύς, βραδύς, ὠκύς, πολύς «πολέων κεκορήμεθ´ ἀέθλων» (ψ 350). τὸ δὲ ἥμισυς προπαροξύνεται. οὐ γὰρ δισύλλαβον. καὶ τὸ θῆλυς προπερισπᾶται «θῆλυς ἐέρση» (Od. ε 467). «Ἥρη θῆλυς ἐοῦσα» (Il. Τ 97)· οὐ γὰρ τριγενές· οὐ δύναται γὰρ εἶναι ἀρσενικὸν τὸ τῆς τῶν γυναικῶν φύσεως κατηγοροῦν. καὶ τὸ πρέσβυς βαρύτονον. μονογενὲς ὄν. καὶ τὸ Λίβυς. διὰ γὰρ τοῦ 'υ' κλίνεται. Πᾶν εἰς 'υς' λῆγον σύνθετον ἐπιθετικὸν βαρύνεται, ἔπηλυς, νέηλυς, πολύδακρυς, μελάνοφρυς. Τὰ εἰς 'υς' ἀρσενικὰ ὑπερδισύλλαβα βαρύνεται, ἥμισυς, πέλεκυς, Ῥαδάμανθυς. ἔστι δὲ ὄνομα βασιλέως, ὄλολυς, ἄσταχυς. σεσημείωται τὸ ἐλαχύς ὁ ἐλάχιστος ὀξυνόμενον. ὀξύνεται δέ, ἐπεὶ τὰ εἰς 'υς' ἔχοντα οὐδετέρου παρασχηματισμὸν παραληγόμενα τῷ 'α' ὀξύνονται οἷον βραδύς, ταχύς, πραΰς. τὴν οὖν ὀφειλομένην προπαροξύτονον τάσιν ἐν τῷ θηλυκῷ ἀνεδέξατο «νῆσος ἔπειτ´ ἐλάχεια» (Od. ι 116). Τὰ εἰς 'υς' θηλυκὰ συνεσταλμένον ἔχοντα τὸ 'υ' καὶ διὰ τοῦ 'δος' κλινόμενα ὀξύνεται, χλαμύς, πηλαμύς, κροκύς, Καινύς νῆσος πλησίον Πελωριάδος τῆς κατὰ Σικελίαν ἄκρας, πρὸς δύσιν νεύουσα. τὰ μέντοι μὴ διὰ τοῦ 'δος' κλινόμενα βαρύνεται, γένυς, πίτυς, χέλυς, γῆρυς, ἀτράφαξυς εἶδος λαχάνου, ἄμαξυς, κόρυς, κῶμυς, ἔγχελυς· οἱ δὲ Ἐγχελεῖς ἔθνος Ἰλλυρικὸν ἢ ἀπὸ τοῦ Ἐγχελής ἢ ἀπὸ τοῦ Ἐγχελεύς. λέγεται καὶ Ἐγχελέαι ἀπὸ τοῦ Ἐγχελέης ἢ Ἐγχελέας. Μῶλυς Λίβυσσα πόλις. Ἑκαταῖος περιηγήσει Λιβύης. Κῶβρυς πόλις Θρᾴκης. Θεόπομπος Φιλιππικῶν ἐνάτῳ. Αἶγυς πόλις Λιγυστική, ὡς Εὐφορίων.
Simple adjectival forms in -υς, declined with ε, being trisyllabic and disyllabic, are accented with an acute: ἠΰς, ἡδύς, ταχύς, βραδύς, ὠκύς, πολύς, “we have had our fill of many contests” (ψ 350). But ἥμισυς is accented with a proparoxytone; for it is not disyllabic. And θῆλυς has a circumflex on the penult: “θῆλυς dew” (Od. ε 467); “Hera, being θῆλυς” (Il. Τ 97): for it is not of three genders; for what predicates the nature of women cannot be masculine. And πρέσβυς is barytone, since it is of one gender; likewise Λίβυς, for it is declined with υ. Every compound adjectival form ending in -υς is barytone: ἔπηλυς, νέηλυς, πολύδακρυς, μελάνοφρυς. Masculine forms in -υς of more than two syllables are barytone: ἥμισυς, πέλεκυς, Ῥαδάμανθυς (it is the name of a king), ὄλολυς, ἄσταχυς. Noted as exceptional is ἐλαχύς, ‘the smallest’, being accented with an acute. It is accented with an acute because forms in -υς that have a neuter formation, with α in the penult, are accented with an acute, as βραδύς, ταχύς, πραΰς. Accordingly, in the feminine it took the proparoxytone accent that is due: “and then an ἐλάχεια island” (Od. ι 116). Feminine forms in -υς with contracted υ and declined through -δος are accented with an acute: χλαμύς, πηλαμύς, κροκύς, Καινύς—an island near Πελωριάς, the promontory in Sicily, inclining westward. Those, however, not declined through -δος are barytone: γένυς, πίτυς, χέλυς, γῆρυς, ἀτράφαξυς (a kind of vegetable), ἄμαξυς, κόρυς, κῶμυς, ἔγχελυς; and the Ἐγχελεῖς are an Illyrian people, either from Ἐγχελής or from Ἐγχελεύς. They are also called Ἐγχελέαι from Ἐγχελέης or Ἐγχελέας. Μῶλυς, a Libyan city: Hecataeus in the Periegesis of Libya. Κῶβρυς, a city of Thrace: Theopompus in the ninth book of the Philippica. Αἶγυς, a Ligurian city, as Euphorion says.