- The definition of illogical is not making sense or going against reason.
An example of something illogical is deciding to buy a $400,000 house because the price has recently been reduced, when the buyer can only realistically afford $200,000.
illogical definition by Webster's New World
Origin: ; from in- plush logical
illogical definition by American Heritage Dictionary
- Contradicting or disregarding the principles of logic.
- Without logic; senseless.
- il·logˌi·calˈi·ty , il·logˈi·cal·ness noun
- il·logˈi·cal·ly adverb