īnsomnis

Vigil denotes the state of being awake as positive, and involves consciousness and will, and the application of vital energy, like ἄγρυπνος; whereas insomnis and exsomnis, only negatively, as sleepless, ἄϋπνος; but the insomnis cannot sleep; the exsomnis will not sleep. Tac. Ann. i. 65. Cum oberrarent tentoriis insomnes magis quam pervigiles. Vell. P. ii. 88. Mæcenas ubi rem vigiliam exigeret, sane exsomnis. Hor. Od. iii. 7, 6. Frigidas noctes non sine multis insomnis lacrimis agit; comp. with 25, 7. Non secus in jugis exsomnis stupet Evias; or Virg. Æn. ix. 167, with vi. 556. (iv. 444.)

1. Somnus (ὕπνος) denotes sleep, as a usual prosaic expression; sopor (ὕπαρ) as a select poetical expression. In prose sopor has only a causative meaning, a means of producing sleep, but not a deep sleep. 2. Somnium denotes a dream, in prose, like ὄναρ; insomnium, in poetry, like ἐνύπνιον. (v. 278.)