Lewis & Short

furtīvus, a, um, adj. [furtum], stolen, purloined, pilfered (class.).

  1. I. Lit.: qui scias mercari furtivas atque ingenuas virgines, Plaut. Curc. 5, 2, 22: liberalis mulier, advecta ex Arabia, id. Pers. 4, 3, 61: haecine illa est furtiva virgo? id. ib. v. 83: lana, Hor. Ep. 1, 13, 14: strigilis, id. S. 2, 7, 110: colores, id. Ep. 1, 3, 20; cf.: vincula rari capilli, Prop. 4, 5, 69 (5, 5, 71 M.): res, Quint. 5, 13, 49; Liv. 45, 39, 6.
  2. II. Transf., in gen., secret, hidden, concealed, furtive, clandestine (class.): furtivum iter per Italiam, * Cic. Pis. 40, 97: expeditiones (with latrocinia, opp. bella), Vell. 2, 31, 2: victoria, Just. 11, 6: amor, Verg. A. 4, 171: libertas, Ov. Am. 2, 2, 15: lectus, Tib. 1, 5, 7: usus, id. 1, 9, 55: mens, Ov. H. 17, 265: scriptum, cipher, Gell. 17, 9, 21: nox, favorable to secrecy, Ov. Am. 1, 11, 3: quem Rhea sacerdos Furtivum partu sub luminis edidit oras, Verg. A. 7, 660: celent furtivos balnea tuta viros, secret, concealed lovers, Ov. A. A. 3, 640: viri, id. P. 3, 3, 56.
    Hence, adv.: furtīve, stealthily, secretly, furtively (very rare; syn.: furtim, clam, secreto, occulte): clam furtive aliquid accipere, Plaut. Poen. 5, 2, 62: quidam furtive agunt gratias et in angulo et ad aurem, Sen. Ben. 2, 23: data munera, Ov. Am. 2, 5, 6.