Lewis & Short

vānus, a, um, adj. [etym. dub.; cf. vaco], that contains nothing, empty, void. vacant.

  1. I. Lit. (rare; not in Cic.): sed illos Exspectata seges vanis elusit aristis, Verg. G. 1, 226: leve ac vanum granum, Col. 2, 9, 13: ne vana urbis magnitudo esset, Liv. 1, 8, 5: vanior jam erat hostium acies, id. 2, 47, 4: videtis ordines raros, cornua extenta, mediam aciem vanam et exhaustam, Curt. 4, 14, 14: vanam aciem esse ratus, i. e. thin, weak, id. 4, 14, 8: non vanae redeat sanguis imagini, i. e. to the shade of the dead (so called as being without a body), Hor. C. 1, 24, 15; 3, 27, 41.
  2. II. Trop., empty as to purport or result, idle, null, groundless, unmeaning, fruitless, vain (freq. and class.): omnes dant consilium vanum, Enn. ap. Front. Ep. 2, 13 (Trag. Rel. v. 419 Vahl.): falsum aut vanum aut fictum (opp. vera), Ter. Eun. 1, 2, 24: oratio, Cic. Lael. 26, 98: vana quaedam atque inania polliceri. id. Planc. 42, 101: vana falsaque, Plin. 30, 2, 5, § 14: res tumida, vana, ventosa, Sen. Ep. 84, 11: orationi vanae crediderunt, idle, delusive, Cic. Rosc. Am. 40, 117: non bellum sed vanam imaginem belli insedisse, Liv. 3, 16, 5: verba, Ov. M. 13, 263: convicia, id. ib. 9, 303: historiae, Quint. 1, 8, 20: argumentum, id. 7, 2, 34: error, Lucr. 1, 1068: agitatio armorum, Liv. 7, 10, 8: metus, Hor. C. 1, 23, 3; Ov. H. 16, 342: gaudia, Hor. Ep. 2, 1, 188: spes, Ov. M. 14, 364: ira, Val. Fl. 8, 374; Liv. 1, 10, 4: fides, Verg. A. 4, 12: omen, Ov. M. 2, 597: vox auguris, id. ib. 3, 349: cuspis, id. ib. 8, 346: pila omnia, Liv. 7, 23, 8: pleraque tela, id. 30, 10, 13: ensis, id. 7, 10, 9: ictus, id. 34, 39, 2: promissa, Tac. A. 3, 16: vana et irrita testamenta, Suet. Calig. 38: vaniore dicendi genere inflata (gens), Quint. 12, 10, 17: sententiarum vanissimus strepitus, Petr. 1.
    With abl.: postquam equestris pugna effectu quam conatibus vanior erat, Liv. 7, 7, 8: oratio non suis vana laudibus, non crimine alieno laeta, id. 4, 41, 1.
      1. 2. Subst.: vānum, i, n., emptiness, nothingness, naught: ad vanum et irritum redacta victoria, brought to nothing, Liv. 26, 37, 8: nec tota ex vano criminatio erat, i. e. groundless, without cause, id. 33, 31, 4: ex vano habere spem, id. 27, 26, 1: cedit labor in vanum, Sen. Hippol. 182.
        Plur.: haud vana adtulere, Liv. 4, 37, 6.
        Neutr. plur. adverb.: ut vidit (Arruntem) laetantem animis ac vana tumentem, i. e. vainly, with vain show, Verg. A. 11, 854.
        With gen.: corruptus vanis rerum, Hor. S. 2, 2, 25: vana rumoris, Tac. A. 4, 59.
      2. 3. Vanum est, with subject-clause: vanum arbitror esse circa canis ortum angues candidos membranam eam exuere, Plin. 30, 3, 8, § 25.
    1. B. Transf., of persons, false, lying, deceptive, delusive, untrustworthy: vanus et perfidiosus et impius, false, Cic. Quint. 6, 26: vanus mendaxque, Verg. A. 2, 80: haruspices, Cic. Div. 1, 19, 36: haec mihi non vani (neque erat cur fallere vellent) Narravere senes, i. e. veracious, Ov. M. 8, 721; cf.: ingenium dictatoris, Liv. 1, 27, 1: vane Ligus frustraque animis elate superbis, Verg. A. 11, 715: vir omnium vanissimus, Vell. 2, 30, 1: invidia vulgi vanum ingenium dictatoris corrupit, weak, wavering, Liv. 1, 27, 1: ne irrisus ac vanus iisdem castris assideret, etc., in vain, Tac. H. 2, 22 fin.
      With gen.: aut ego (i. e. Juno) veri Vana feror, Verg. A. 10, 631: voti vanus, i. e. deceived, Sil. 12, 261: turba vana sanctitudinis, App. de Deo Socr. p. 43, 1.
      1. 2. Esp., vainglorious, ostentatious, boastful, vain: Cn. Lentulus perincertum stolidior an vanior, Sall. H. 4, 35 Dietsch ad loc.: laudare se vani, vituperare stulti est, Val. Max. 7, 2, ext. 8.
        With abl.: hunc ingenio vanum Aetoli inpulerant in spem regni, Liv. 35, 47, 7.
        Hence, adv.: vānē, idly, vainly (post-class.): vane gaudere, Tert. Apol. 49: vanius excogitatum, App. Mag. p. 300, 41: praecavere vanissime, Tert. Pud. 1.