ill·ness (?l?n?s)n.1. a. Poor health resulting from disease of body or mind; sickness.b. A disease.2. Obsolete a. The quality of being disagreeable or unpleasant.b. Evil; wickedness.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.illness (??ln?s) n1. a disease or indisposition; sickness2. a state of ill health3. obsolete wickednessCollins English Dictionary ? Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014ill?ness (??l n?s) n. 1. unhealthy condition; poor health; indisposition; sickness. 2. Obs. wickedness. [1490?1500] Random House Kernerman Webster’s College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.illnessaccession – Can be the “onset of illness or a powerful feeling.”allopathy, homeopathy – Allopathy is treatment to suppress the symptoms of illness using the principle of opposites, while homeopathy encourages, rather than suppresses, the body’s reaction to an illness.idiopathic disease – An illness of unknown cause.languor – Any distressed condition, such as illness, sorrow, fatigue, etc.Farlex Trivia Dictionary. © 2012 Farlex, Inc. All rights reserved.illness – disease1. ‘illness’If you have an illness, there is something wrong with your health. An illness can last for a long time or a short time, and its effects can be serious or not serious.You can use the adjectives long and short in front of illness, but not in front of disease.A disease is a particular kind of illness caused by bacteria or an infection. Diseases can often be passed from one person to another.Animals and plants can also have diseases, but not illnesses.