Related Clues:

• Sung by a group
• Unkeyed
• Lacking a musical key
• Like some modern music
• Without a key
• Unaccented
• Musically keyless
• Lacking a key, in music
• Discordant, musically
• Like much modern music
• Hard-to-hum
• Lacking a key center
• Lacking a musical quality
• Unmelodious
• Like Muddy Waters's music