Lewis & Short

monstro, āvi, ātum, (archaic mostro; v. Brix ad Plaut. Trin. 2, 2, 61), 1, v. a. [like monstrum, from moneo], to show, point out, to indicate, intimate, inform, advise, teach, instruct, tell any thing (in class. prose very rare, and only in the lit. signif.; in Cic. only a few times; in Cæs. and Sall. not at all; syn.: indico, significo, ostendo, exhibeo).

  1. I. In gen.: qui erranti comiter monstrat viam, Enn. ap. Cic. Off. 1, 16, 51 (Trag. v. 387 Vahl.); cf.: qui sibi semitam non sapiunt, alteri monstrant viam, id. ap. Cic. Div. 1, 58, 132 (Trag. v. 358 Vahl.): iter, Curt. 5, 13, 9: palmam, Cic. Leg. 1, 1, 2: digito, Hor. S. 2, 8, 26; Pers. 1, 28: monstra quod bibam, Plaut. Men. 5, 1, 42; Ter. Ad. 4, 2, 31: tu … si quid librari … non intellegent, monstrabis, i. e. dices, Cic. Fam. 16, 22, 1: res gestae … Quo scribi possent numero, monstravit Homerus, Hor. A. P. 73: inulas ego primus amaras Monstravi incoquere, id. S. 2, 8, 51 sq.: monstrate mearum Vidistis si quam hic errantem forte sororum, Verg. A. 1, 321: cujus prudentia monstrat Summos posse viros … nasci, etc., Juv. 10, 48.
    Pass.: quod monstror digito praetereuntium, Hor. C. 4, 3, 22.
    Impers. pass.: si voles advortere animum, comiter monstrabitur, Enn. ap. Varr. L. L. 7, § 89 Müll. (Trag. v. 386 Vahl.).
  2. II. In partic.
    1. A. To ordain, institute, appoint (poet.): monstratas excitat aras, appointed, Verg. G. 4, 549: piacula, id. A. 4, 636: ignis, Ov. Tr. 3, 11, 53.
    2. B. To indict, impeach for a crime, to denounce, accuse, inform against (post-Aug.): alii ab amicis monstrabantur, were pointed out, informed against, Tac. H. 4, 1: Nerone Scribonios fratres … ad exitium, id. ib. 4, 41.
    3. C. To advise a person in any manner, or to do any thing: alicui bene, Plaut. Bacch. 1, 2, 25: non periclumst ne quid recte monstres, id. Ps. 1, 3, 55: conferre manum pudor iraque monstrat, advise, urge, Verg. A. 9, 44.
      Hence, monstrātus, a, um, P. a., conspicuous, distinguished, remarkable (Tacitean): et hostibus simul suisque monstrati, Tac. G. 31: propinquitate Galbae monstratus, id. H. 1, 88.