Possible Clues:

• Its bark is worse than its bite?
• One misleadingly appearing threatening
• No real threat
• Person feigning power
• *One who's an empty threat
• Toothless adversary (or something that can be made in 39-Down)
• Bluff-and-bluster type
• At the start of 15 across, beastly circus type has bark louder than its bite
• Nothing to be afraid of, really
• Part of exam, oddly, I get right -- not a real threat