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.
appalling
The definition for appalling is "Inspiring dismay or disgust." Used in a sentence: Hector found his roommate's habit of leaving his dirty socks on the floor appalling.
corrosive
The definition for corrosive is "Bitingly sarcastic." Used in a sentence: The cruel Estella's corrosive comments made Pip cry.
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.
gargantuan
The definition for gargantuan is "Gigantic." Used in a sentence: The gargantuan monster towered over the ten–story bulding.