Lewis & Short

nicto, āvi, ātum, 1, and ĕre, 3, v. n., and nictor, ātus, v. dep. n. [1. nico], to move the eyelids.

  1. I. Lit., to move the eyelids up and down, to wink, blink: plerisque naturale ut nictari (al. nictare) non cessent, Plin. 11, 37, 54, § 144; 11, 37, 57, § 156.
    Form nicto, ĕre: (canis) voce suā nictit ululatque ibi acute, Enn. ap. Paul. ex Fest. p. 177 Müll. (Ann. v. 346 Vahl.).
      1. 2. To make a sign with the eyes, to wink: neque illa ulli homini nutet, nictet, annuat, Plaut. As. 4, 1, 39; id. Men. 4, 2, 49; id. Merc. 2, 3, 72.
    1. B. Transf., of fire: nictantia fulgura flammae, flashing, Lucr. 6, 182.
  2. II. Trop., to exert one’s self, to strive: nictare et oculorum et aliorum membrorum nisu saepe aliquid conari, dictum est ab antiquis, ut Lucretius in libro quarto (6, 836): Hic ubi nictari nequeunt (Lachm. nixari): Caecilius in Hymnide: Garrulis medentes jactent, sine nictentur perticis, Paul. ex Fest. p. 177 Müll.