[ il-di-fahynd ]
See synonyms for ill-defined on
  1. badly or inadequately defined; vague: He confuses the reader with ill-defined terms and concepts.

Origin of ill-defined

First recorded in 1865–70

Words Nearby ill-defined Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use ill-defined in a sentence

  • Its powers are ill-defined; I could but treat with its members as with private individuals, besides which they are Spaniards.

    Ponce de Leon | William Pilling
  • Then, in about 1870, came the discovery of the diamond-fields, situated on the then still ill-defined western limits of the State.

  • In the distance behind Gommecourt there is some ill-defined rising ground forming gullies and ravines.

    The Old Front Line | John Masefield
  • Clouded: Having a pale ground, with ill-defined patches of a deeper tint (Fig. 145, c).

  • Some of the above, as the notion of elementary and celestial nature, and rarity, are vague and ill defined.

    Novum Organum | Francis Bacon

British Dictionary definitions for ill-defined


  1. imperfectly defined; having no clear outline

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012