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.
diffident
The definition for diffident is "Lacking self–confidence." Used in a sentence: The diffident student never raised her hand in class, even when she knew the answer.
ethical
The definition for ethical is "Conforming to accepted standards." Used in a sentence: Mary did the ethical thing and turned in the diamond necklace she found.
eulogy
The definition for eulogy is "Speech or writing in praise of deceased." Used in a sentence: Ernesto delivered a moving eulogy at his uncle's funeral.
fidelity
The definition for fidelity is "State of being faithful." Used in a sentence: Unlike her fickle friend Benji, May Belle was known for her fidelity.