Related Clues:

• Meaningless
• Like some promises
• Quell
• Render ineffective
• Hit 'back'
• Go back a step, in word processing
• Put back the way things were
• Reverse an action
• Reverse, as an action
• Drain to the bottom
• Word-processor command
• Free of knots
• Clean out
• Make disappear
• Scrub, as a mission