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

• εἰ δὲ ἐπιστραφέντεσ ἐσ κύκλουσ ὑπὲρ τὰ κέρατα παρελαύνειν ἐθέλοιεν, ἀνατείνεσθαι ἐσ τὰ ὑπερδεξιώτερα ἔτι τὰ κέρατα αὐτῆσ τῆσ ψιλῆσ τοξείασ· (Arrian, Acies Contra Alanos 40:1)
• ἐπεὶ δὲ ἤδη σφᾶσ κατὰ τὴν Ζάκυνθον εἶναι ἀπὸ ψιλῆσ τῆσ κεραίασ πλέοντασ, ἔτι καὶ σπείρασ τινὰσ ἐπισυρομένουσ, ὡσ τὸ ῥόθιον ἐπιδέχεσθαι τῆσ ὁρμῆσ, περὶ μέσασ νύκτασ οἱο͂ν ἐν τοσούτῳ σάλῳ ναυτιάσαντα τὸν Δάμωνα ἐμεῖν ἐκκεκυφότα ἐσ τὴν θάλασσαν εἶτα, οἶμαι, τῆσ νεὼσ βιαιότερον ἐσ ὃ ἐκεκύφει μέροσ ἐπικλιθείσησ καὶ τοῦ κύματοσ συναπώσαντοσ, ἐκπεσεῖν αὐτὸν ἐπὶ τὴν κεφαλὴν ἐσ τὸ πέλαγοσ, οὐδὲ γυμνὸν τὸν ἄθλιον,^ ὡσ ἂν καὶ ῥᾷον δύνασθαι νεῖν. (Lucian, Toxaris vel amicitia, (no name) 19:8)
• δεδειγμένησ τῆσ διαφορᾶσ ᾗ διαφέρει μουσικὴ λογικῆσ λοιπὸν ἂν εἰή κἀκεῖνα λέγειν, ὅτι τὸ μὲν τῆσ φωνῆσ μέλοσ, λέγω δὲ οὐ τῆσ ᾠδικῆσ ἀλλὰ τῆσ ψιλῆσ, ἐὰν ἡδέωσ διατιθῇ τὴν ἀκοήν, εὐμελὲσ λέγοιτ’ ἄν, ἀλλ’ οὐκ ἐμμελέσ· (Dionysius of Halicarnassus, De Compositione Verborum, chapter 1144)
• ἄρξομαι δὲ πρῶτον ἀπὸ τῆσ ψιλῆσ λέξεωσ, ἕνα τῶν ἀνδρῶν προχειρισάμενοσ ὃν ἐν τοῖσ μάλιστα οἶμαι τὴν ποιητικὴν ἐκμεμάχθαι φράσιν, βουλόμενοσ μὲν καὶ πλείουσ, οὐκ ἔχων δὲ χρόνον ἱκανὸν ἅπασι. (Dionysius of Halicarnassus, De Compositione Verborum, chapter 252)
• ἄλλα γὰρ ἐν ἄλλαισ εὐθηνεῖ χώραισ, εἶτα περὶ γεωργίασ, καὶ ταύτησ ἤδη ψιλῆσ τε καὶ πεφυτευμένησ, καὶ μελιττουργίασ, καὶ τῶν ἄλλων ζῴων τῶν πλωτῶν ἢ πτηνῶν, ἀφ’ ὅσων ἔστι τυγχάνειν βοηθείασ. (Aristotle, Politics, Book 1 147:1)

Source: Ancient Greek entries from Wiktionary