Related Clues:

• Crowded
• Packed tight
• Obtuse
• In la-la land
• None too smart
• Like thick fog
• Tightly packed
• Lightheaded
• Not too bright
• Not too astute
• Scatterbrained
• Slow on the uptake
• Not the brightest bulb on the tree
• Not very logical
• Hardly qualified to be a rocket scientist