Possible Clues:

• Slow-moving, being like heavy metal
• Tough to move
• Depressing — heavy
• Bandleader dismisses bard as dull
• Gloomy main actor — heartless, even
• Grey retreat south of meadow
• Like the feeling of one's legs after a marathon, maybe
• Dull and heavy
• Dull learner with a need for redirection
• The French foreign port lacking interest