adversary
The definition for adversary is "One who opposes or resists." Used in a sentence: Franklin hoped to defeat his adversary in the afternoon's tennis match.
authoritarian
The definition for authoritarian is "Favoring absolute obedience to authority." Used in a sentence: Marco's authoritarian mother never allowed him to watch more than one hour of television a day.
foil
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.
mundane
The definition for mundane is "Practical, ordinary." Used in a sentence: The flighty Caroline could not be troubled with mundane tasks such as paying her bills.
procrastinate
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."