-φι

• -φῐν (-phin) — with movable nu, before a vowel

From the Proto-Indo-European instrumental plural inflection *-bʰi(s), reanalyzed as a suffix. Cognate with Sanskrit भिस् (-bhis, “plural instrumental marker”), Old Armenian -ւ (-w).

-φῐ • (-phi) (Epic)

1. Creates a transnumeral case-form used with several different meanings:
   1. instrumental
      • 800 BCE – 600 BCE, Homer, Odyssey 9.407–408:

        τοὺς δ’ αὖτ’ ἐξ ἄντρου προσέφη κρατερὸς Πολύφημος·
        ὦ φίλοι, Οὖτίς με κτείνει δόλῳ οὐδὲ βίηφιν.

        toùs d’ aût’ ex ántrou proséphē krateròs Polúphēmos;
        ô phíloi, Oûtís me kteínei dólōi oudè bíēphin.

        Mighty Polyphemus addressed back out of his cave:
        "Friends, No One is killing me by neither cunning nor force."

      • 800 BCE – 600 BCE, Homer, Odyssey 4.704–705:

        τὼ δέ οἱ ὄσσε
        δακρυόφιν πλῆσθεν

        tṑ dé hoi ósse
        dakruóphin plêsthen

        's two eyes filled with tears

   2. locative
      • 800 BCE – 600 BCE, Homer, Odyssey 9.237–239:

        αὐτὰρ ὅ γ’ εἰς εὐρὺ σπέος ἤλασε πίονα μῆλα,
        πάντα μάλ’, ὅσσ’ ἤμελγε, τὰ δ’ ἄρσενα λεῖπε θύρηφιν,
        ἀρνειούς τε τράγους τε, βαθείης ἔντοθεν αὐλῆς.

        autàr hó g’ eis eurù spéos ḗlase píona mêla,
        pánta mál’, hóss’ ḗmelge, tà d’ ársena leîpe thúrēphin,
        arneioús te trágous te, batheíēs éntothen aulês.

        And drove into the wide cave his fat sheep,
        all of them that he would milk, but left the males at the door, the rams and billy-goats, inside the deep courtyard.

   3. ablative, often with the prepositions ἐκ (ek) and ἀπό (apó)
      • 800 BCE – 600 BCE, Homer, Odyssey 2.1–3:

        ὤρνυτ’ ἄρ’ ἐξ εὐνῆφιν Ὀδυσσῆος φίλος υἱός

        ṓrnut’ ár’ ex eunêphin Odussêos phílos huiós

        Odysseus's son awoke and got out of bed

   4. (rare) genitive
      • 800 BCE – 600 BCE, Homer, Iliad 5.41:

        διὰ δὲ στήθεσφιν ἔλασσε

        dià dè stḗthesphin élasse

        and drove it through his chest

   5. (rare) dative
      • 800 BCE – 600 BCE, Homer, Odyssey 3.110:

        Πάτροκλος, θεόφιν μήστωρ ἀτάλαντος

        Pátroklos, theóphin mḗstōr atálantos

        Patroclus, a counselor equal to the gods

• Smyth, Herbert Weir (1920) “Part II: Inflection”, in A Greek grammar for colleges, Cambridge: American Book Company, § 280
• William Bedell Stanford (1959) . "Introduction, Grammatical Introduction". Homer: Odyssey I-XII 1 (2nd ed.). Macmillan Education Ltd. p. lx.