• A little loopy
• Addlebrained
• Air-headed
• Bubble-headed
• Clueless
• Easily addled
• Easily confused
• Eccentric to be kind
• Empty-headed
• Flaky
• Flibbertigibbety
• Flighty, in slang
• Inanely silly
• Lightheaded
• Like a space cadet
• Like an airhead
• Like an eccentric uncle
• Like one whose elevator doesn't go all the way to the top
• Like Phoebe on Friends
• Not at all analytical
• Not very logical
• Rattlebrained
• Scatterbrained
• Wacko