lunatic Meaning, Definition & Usage

  1. noun an insane person
    madman; maniac.
  2. noun a reckless impetuous irresponsible person
    harum-scarum; swashbuckler; madcap; daredevil; hothead.
  3. adjective satellite insane and believed to be affected by the phases of the moon
    moonstruck.

WordNet

Lu"na*tic adjective
Etymology
F. lunatique, L. lunaticus, fr. luna the moon. See Lunar.
Definitions
  1. Affected by lunacy; insane; mad.
    Lord, have mercy on my son; for he is lunatic. Wyclif (Matt. xvii. 15).
  2. Of or pertaining to, or suitable for, an insane person; evincing lunacy; as, lunatic gibberish; a lunatic asylum.
Lu"na*tic noun
Definitions
  1. A person affected by lunacy; an insane person, esp. one who has lucid intervals; a madman; a person of unsound mind.
    The lunatic, the lover, and the poet, Are of imagination all compact. Shak.

Webster 1913