Addle means to confuse or muddle someone's thinking. When something addles your brain, it makes your thoughts fuzzy and unclear, like trying to think straight when you're exhausted or distracted.

The word often appears as addled, describing a confused state of mind. After spinning around ten times, you might feel addled and dizzy, unable to think clearly. A student might have an addled brain after studying too many subjects in one night. The heat of a summer afternoon can leave people feeling addled and unable to concentrate.

When applied to thinking, it suggests that normal mental processes have gotten scrambled.

You might hear someone say their mind is addled by worry, or that too much information has left them feeling addle-brained. The word captures that frustrating moment when you know you should be thinking clearly but your brain just won't cooperate, like a computer that's running too many programs at once and starts moving slowly.