To be addled is to be fuzzy in the head, a little foggy and confused. When you're addled, you're having trouble thinking. If your favorite movie star walks by and says hello, you might be too addled to say hi back.
Sometimes it's hard to think and you feel slow and befuddled. When your brain feels like it's stuck in some mental mud, you're addled. People are addled for many reasons. When you first wake up, you probably feel addled. Drinking too much makes people feel addled. A confusing situation can make you feel addled. Being in love, star struck, drunk, sleepy, or sick can make you feel addled. Avoid big decisions and important tests when you’re addled!