Related Clues:

• Group with no members, in math
• Tear up, so to speak
• Invalidated
• Word on a check
• Invalidate, as a check
• Null and ___
• Null and --
• It has zero measure, in math
• "___ where prohibited"
• Tear up, as a check
• Not occupied
• Empty like space
• Null and empty
• Containing nothing or not legally binding
• Empty space or vacuum