Flake
• Crazoid
• Bananas
• Bonkers
• Crazy
• Cuckoo
• Deranged
• Eccentric
• Far-out
• Kook
• Loony
• Loony one
• Lunatic
• More than odd
• Nut case
• Nut job
• Nuts
• Nutzoid
• Odd fellow
• Oddball
• Off the wall
• Screwball
• Screwy
• Strange fellow
• Weird one