Related Clues:

• Riverboat hazard
• See 12-Across
• Hidden obstruction
• Holdup cause
• Problem with a fishing line
• Complication
• Unforeseen hangup
• Hose flaw
• Hosiery fault
• Planning problem
• Run producer
• It holds things up or slows things down
• Hidden catch
• Hosiery hang-up
• Hindrance to progress