imbecility Meaning, Definition & Usage

  1. noun retardation more severe than a moron but not as severe as an idiot
  2. noun a stupid mistake
    betise; stupidity; folly; foolishness.

WordNet

Im`be*cil"i*ty noun
Etymology
L. imbecillitas: cf. F. imbécillité.
Wordforms
plural Imbecilities
Definitions
  1. The quality of being imbecile; weakness; feebleness, esp. of mind.
    Cruelty . . . argues not only a depravedness of nature, but also a meanness of courage and imbecility of mind. Sir W. Temple.
    ✍ This term is used specifically to denote natural weakness of the mental faculties, affecting one's power to act reasonably or intelligently. Syn. -- Debility; infirmity; weakness; feebleness; impotence. See Debility.

Webster 1913