Related Clues:

• Pain reliever
• Resistance of a sort
• Morphine, e.g.
• Wearisome task
• Resistance
• Race on a strip
• Quarter-mile race, e.g.
• Friction between engine parts
• Sense-dulling drug
• Boring time
• Pull laboriously
• Pass slowly
• Zip strip?
• Boring thing
• It may induce relaxation