The definition for egotist is "Self–important person." Used in a sentence: Darren dreaded carpooling with the egotist Shelly, who talked about herself nonstop.

The definition for euphoria is "Feeling of great happiness." Used in a sentence: Cassandra was overcome with euphoria when she met her long–lost sister.

The definition for foil is "One that enhances or underscores by contrast." Used in a sentence: The sweet cookie was a perfect foil to the sour lemon sorbet.

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 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.