I.v. inch. n. [rarus], to grow thin, lose its density, to become rare, be rarefied (poet. and in post-Aug. prose).
I. Lit.: “fulgit item cum rarescunt quoque nubila caeli,” Lucr. 6, 214; cf. id. 6, 513; Stat. S. 1, 2, 186: “umor aquai ab aestu,” Lucr. 6, 875; cf.: “rarescit terra calore,” becomes loose, id. 6, 841: “corpus,” id. 4, 865; 892: “resolutaque tellus In liquidas rarescit aquas,” Ov. M. 15, 246: “quadrupedibus senectute lanae rarescunt,” Plin. 11, 39, 94, § 231.—
II. Transf.: “rarescunt alta colonis Maenala,” i. e. become empty, depopulated, Stat. Th. 4, 284; cf.: “moenia densae Romae,” id. S. 4, 4, 14: rarescit multo laxatus vulnere miles, the ranks grow thin, Sil. 17, 423; 5, 382; and: “rarescunt cuspide pugnae,” Val. Fl. 6, 617: “umbrae rarescentes,” Stat. Th. 1, 343; 11, 74: ubi angusti rarescent claustra Pelori, i. e. shall open themselves, grow wider, i. q. laxabuntur, patebunt, * Verg. A. 3, 411; so, “colles paulatim rarescunt,” Tac. G. 30.—
III. Trop.: “sonitus rarescit,” becomes feeble, diminishes, dies away, Prop. 3, 15 (4, 14), 35: “quod justitia rarescit, iniquitas increbrescit,” Tert. Apol. 20: “ita justitia rarescet, ita impietas et avaritia crebrescent,” Lact. 7, 15, 8: “Ibis efficit, ut rarescant mortiferae pestes absumptae,” become rare, Amm. 22, 15, 25; 26, 3, 1. (In Ov. M. 15, 246, the read. varies between rarescit and rorescit.)
