Sense

1. naked, bare
2. bald, smooth
3. unclad, uncovered
4. small, frail, delicate
5. (military) light (troops)
6. unarmed
7. (of words) without meter (i.e. prose)
8. (poetry) without music (Epic vs Lyrical)
9. (singing) without music (a capella)
10. (music) without singing (instrumentals)
11. (grammar) without the rough breathing (i.e. with the smooth breathing)
12. (grammar) describing the unaspirated voiceless stops, π ‎(p), τ ‎(t), κ ‎(k), as opposed to the aspirated voiceless stops, φ ‎(ph), χ ‎(kh), θ ‎(th)

Examples

• ὁ μὲν γὰρ Ἆπισ, ὁ μέγιστοσ αὐτοῖσ θεόσ, ἐὰν ἀποθάνῃ, τίσ οὕτω περὶ πολλοῦ ποιεῖται τὴν κόμην ὅστισ οὐκ ἀπεξύρησε καὶ ψιλὸν ^ ἐπὶ τῆσ κεφαλῆσ τὸ πένθοσ ἐπεδείξατο, κἂν τὸν Νίσου ἔχῃ πλόκαμον τὸν πορφυροῦν; (Lucian, De sacrificiis, (no name) 15:3)
• καὶ ἔνθεν ἐσ τὸ Ψιλὸν καλούμενον στόμα τοῦ Ἴστρου διακόσιοι καὶ χίλιοι. (Arrian, Periplus Ponti Euxini, chapter 20 5:3)
• αὐτίκα τῶν πεζῶν ἡ ὅπλισισ, ὥσ γε δὴ ἐσ τὰ ἀνωτάτω τεμεῖν, τριχῆ νενέμηται, ἔσ τε τὸ ὁπλιτικὸν καὶ ἐσ τὸ ψιλὸν καὶ ἐσ τὸ πελταστικόν. (Arrian, chapter 3 1:2)
• πρὶν μὲν ἔχων βερβέριον, καλύμματ’ ἐσφηκωμένα, καὶ ξυλίνουσ ἀστραγάλουσ ἐν ὠσὶ καὶ ψιλὸν περὶ πλευρῇσι δέρριον βοόσ, νήπλυτον εἴλυμα κακῆσ ἀσπίδοσ, ἀρτοπώλισιν κἀθελοπόρνοισιν ὁμιλέων ὁ πονηρὸσ Ἀρτέμων,6 κίβδηλον εὑρίσκων βίον, πολλὰ μὲν ἐν δουρὶ τιθεὶσ αὐχένα, πολλὰ δ’ ἐν τροχῷ, πολλὰ δὲ νῶτα σκυτίνῃ μάστιγι θωμιχθείσ, κόμην πώγωνὰ τ’ ἐκτετιλμένοσ· (Athenaeus, The Deipnosophists, Book 12, book 12, chapter 46 1:2)
• "τοῦτο μὲν ὅτι ὁ λαγὼσ ὑπὸ πάντων θηρεύεται, καὶ θηρίου καὶ ὄρνιθοσ καὶ ἀνθρώπου, οὕτω δή τι πολύγονόν ἐστιν, ἐπικυίσκει τε μόνον πάντων θηρίων, καὶ τὸ μὲν δασὺ τῶν τέκνων ἐν τῇ γαστρί, τὸ δὲ ψιλόν, τὸ δὲ ἄρτι ἐν τῇσ μήτρῃσι πλάσσεται, τὸ δ’ ἐπαναιρέεται. (Athenaeus, The Deipnosophists, Book 9, book 9, chapter 63 1:2)

Source: Ancient Greek entries from Wiktionary