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. The definition for revive is "to bring back to life.", the definition for exasperation is "The state of being irritated.", and the definition for negate is "To make invalid."

The definition for preclude is "To rule out in advance." Used in a sentence: "Having cake now will preclude dessert later," said Amber's mother. The definition for unscrupulous is "lacking principles.", the definition for placebo is "An inactive substance used in medical testing.", and the definition for preclude is "To rule out in advance."

The definition for periodic is "Occurring at regular intervals." Used in a sentence: The periodic innterruptions of the cuckoo clock prevented Li from concentrating. The definition for preclude is "to rule out in advance.", the definition for demeanor is "Behavior towards others.", and the definition for corroborate is "To support with evidence."

The definition for parity is "Equality." Used in a sentence: Hilda, to avoid squabbles, aimed for parity in the slices of birthday cake. The definition for pretense is "false intention or purpose.", the definition for drub is "To defeat decisively.", and the definition for impenitent is "Lacking remorse."

The definition for compulsion is "An irresistible impulse." Used in a sentence: Tamar, a shoe fanatic, could not resist the compulsion to buy the shiny red boots. The definition for repel is "to resist, reject.", the definition for penurious is "Extrememly stingy.", and the definition for rhapsody is "State of great happiness."