illogical

adjective

il·​log·​i·​cal (ˌ)i(l)-ˈlä-ji-kəl 

1

: not observing the principles of logic

an illogical argument

2

: devoid of logic : senseless

illogical policies

illogicality

(ˌ)i(l)-ˌlä-jə-ˈka-lə-tē 

noun

illogically

(ˌ)i(l)-ˈlä-ji-k(ə-)lē 

adverb

illogicalness

(ˌ)i(l)-ˈlä-ji-kəl-nəs 

noun

Synonyms of illogical

• unreasonable
• irrational
• unreasoning
• illegitimate

Examples of illogical in a Sentence

It is illogical to think that things will change on their own.

the illogical claim that playing basketball makes people taller because one sees so many tall players

Recent Examples on the Web

Indescribable, illogical, and oh-so powerful belief. —Dieter Kurtenbach, Mercury News, 12 Jan. 2026

In a show full of people doing dumb stuff, Anna is doing dumb stuff for ambiguous reasons, though nearly every aspect of her character is rendered either perplexing or illogical in the finale. —Daniel Fienberg, HollywoodReporter, 8 Jan. 2026

However, the market is made up of both sensible and irrational participants, and all of that action, both the logical and illogical, is going to be reflected in the stock chart. —Zev Fima, CNBC, 30 Dec. 2025

Yet the Administration not only acts as if residency is a magic condition but offers a completely illogical and contradictory definition of what residency is. —Amy Davidson Sorkin, New Yorker, 8 Dec. 2025

Word History

First Known Use

1588, in the meaning defined at sense 1

Rhymes for illogical

• zoological
• aetiological
• anthropological
• archaeological
• axiological
• climatological
• deontological
• dermatological
• eschatological
• etiological
• etymological
• gerontological

Kids Definition

illogical

adjective

il·​log·​i·​cal (ˈ)il-ˈ(l)äj-i-kəl 

: not using or following good reasoning

illogically

-i-k(ə-)lē 

adverb