The definition for negate is "To make invalid." Used in a sentence: Paula negated Tiffany's argument by proving that her main premise was false.

The definition for placebo is "An inactive substance used in medical testing." Used in a sentence: Tom, who had taken the placebo, found that his allergy symptoms did not go away.

The definition for plaudits is "Enthusiastic approval." Used in a sentence: Allison's painting met with plaudits from the critics, who had dismissed her earlier work.

The definition for procrastinate is "To put off intentionally." Used in a sentence: Yvonne's father urged, "Don't procrastinate. Clean your room right away."

The definition for stealth is "The act of moving secretly or unnoticed." Used in a sentence: The burglar took the ring by stealth, slipping it from the sleeping woman's finger.