corrective
The definition for corrective is "Intended to correct." Used in a sentence: The school decided to take corrective measures to prevent truancy.
lenient
The definition for lenient is "Mild or tolerant." Used in a sentence: The judge issued a lenient sentence because it was Frank's first offense.
placebo
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.
repel
The definition for repel is "To resist, reject." Used in a sentence: The soldiers made a massive charge to repel the invaders.
retroactive
The definition for retroactive is "effective as of a prior time or condition." Used in a sentence: The retroactive law made even past infractions punishable.