cunning
The definition for cunning is "Showing clever insight." Used in a sentence: The general devised a cunning strategy to outfox the enemy.
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.
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.
frugal
The definition for frugal is "Thrifty, cheap." Used in a sentence: The frugal shopper only bought items that were on sale.
rancorous
The definition for rancorous is "Marked by deep ill–will." Used in a sentence: The rancorous competition between the two chess clubs actually ended in a brawl.