Illogically means in a way that doesn't follow the rules of sound reasoning or that makes no sense. When someone argues illogically, they might jump to conclusions without evidence, contradict themselves, or ignore obvious facts.

Imagine a student who illogically concludes that studying made them do worse on a test because they studied hard once and got a B, forgetting about the dozens of other times studying helped. Or picture someone who argues illogically that all dogs are dangerous because one dog once barked at them. These conclusions don't follow from the evidence.

The word comes from logic, which is the science of correct reasoning. When you think logically, you follow clear steps from evidence to conclusion, like a detective solving a mystery. When you think illogically, you skip steps, ignore contradictions, or let feelings override facts. You might illogically refuse to go outside because it rained yesterday, even though today is sunny. You might illogically blame your alarm clock for making you late when you chose to hit snooze five times.

The opposite of illogically is logically, meaning in a way that makes sense and follows clear reasoning.