Related Clues:

• Black key, at times
• Lacking sparkle
• Comb's target
• Traffic jam, e.g.
• Lacking bubbles
• Tangled mass
• Wolf's warning
• Freeway problem
• __ as a pancake
• Utterly
• Mongrel's warning
• Low, musically
• Tress distress
• Pitched poorly?
• Lacking fizz