1. Lacking sense or discretion
   - rattlebrained, rattlepated, scatty [Brit] 
2. Guided by whim and fancy
   - flighty, flyaway, head-in-the-clouds

See also: foolish, frivolous

• reclaimed
• Myrtus communis
• myself
• Mysidacea
• Mysidae
• Mysis
• Mysoline
• mysophilia
• mysophobia
• mysophobic
• Mysore
• Mysore thorn
• mystagogue
• mystagogy
• mysterious
• mysteriously
• mysteriousness
• mystery
• mystery novel
• mystery play
• mystery story
• mystic
• Mystic Jewel
• mystical
• mystically