Related Clues:

• Hose problem
• Hiccup
• Bottleneck
• Hosiery woe
• Unseen problem
• Catch-22
• Problem
• Unexpected wrinkle
• Riverboat hazard
• See 12-Across
• Flaw in the system
• Hidden obstruction
• Holdup cause
• Problem with a fishing line
• Complication