Possible Clues:

• A dim-witted constable in 'Measure for Measure'
• Tennis --
• Reef album from 1999
• Funny-bone neighbor
• Half-heartedly shake up the joint
• Metallic joint
• Hinge joint
• Barge returning with nobles inside
• Joint causes bowel disorder
• Appropriately, word that can precede the first words of 10- and 20-Across and 32- and 38-Down