catastrophic
The definition for catastrophic is "Relating to extreme misfortune." Used in a sentence: The effects of the massive hurricane were catastrophic.
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.
revoke
The definition for revoke is "To cancel by taking back." Used in a sentence: After Kal's father revoked his allowance, he had no money for the movies.
solace
The definition for solace is "Source of consolation." Used in a sentence: Parents' weekend was a solace to Marjorie, whose beloved daughter had left for college.
straddle
The definition for straddle is "To favor opposing sides." Used in a sentence: Kia straddled the issue, not wanting to say whether James or Tara was right.