Related Clues:

• Obscures
• Beclouds, with 'up'
• Dims
• Darkens
• Muddles
• Heavy mists
• Reasons for lighthouses
• They're hard to see through
• Makes indistinct
• Frequent San Francisco conditions
• Confused states
• Bewildered mental states
• Mists
• Airport dangers
• Obscures, in a way, with "up"