Related Clues:

• Thorn in one's side
• Annoyer
• Aphid, to a gardener
• Exterminator's target
• Termite, e.g.
• Destructive insect
• Vexatious sort
• Irksome sort
• Insect
• Troublesome insect
• Obnoxious person
• 10 Across or 49 Across
• Flea, e.g.
• Sitter's challenge
• Pain in the butt