Possible Clues:

• Given to causing unnecessary panic
• (Person) creating unnecessary panic
• One crying wolf
• One may cause panic, finding weapon in a tip
• One overstating danger
• Boy who cried wolf, e.g.
• Larry is making an unnecessary fuss about being in a fog
• Scaremonger - the boy who cried wolf was one
• A slim tar (anag.)
• "The sky is falling!" crier, for one