λεπτύν-ω · leptyn-ō — LSJ
make thin or meagre, αἱ ταλαιπωρίαι λ. [τὰ πρόβατα] Arist. HA 596a29, cf. Pr. 882a27; λ. τὸ σχῆμα [τῶν ταγμάτων] Plb. 3.113.8 (cf. λεπτυσμός) ; φωνὴν βαρεῖαν . . λεπτύνων Babr. 103.5:—Pass., to be reduced, grow lean or slender, Hp. Aph. 2.7, Arist. HA 518b29, al.; τοὺς ὤμους λεπτύνεσθαι X. Smp. 2.17; λελεπτυσμένος (-ισμένος cod.) κατὰ τὴν οὐράν, of a serpent, Philum. Ven. 18.1; of things, to be rarefied, Damox. 2.28, cf. Ph. 1.642, S.E. M. 10.25.
comminute or liquefy food in digestion, Plu. QConv. 2.689d; -ύνουσα δίαιτα diet productive of thin humours, Gal. Vict.Att. 3:—Pass., become fluid, opp. παχύνεσθαι, of foods, Hp. VM 19; also -όμενα εἰς πνεῦμα διακρίνεται Arist. Pr. 966b14.
thresh, winnow, λ. Δηοῦς καρπόν AP 9.21.