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.

The definition for gruff is "Rough or stern in manner or speech." Used in a sentence: Heidi's grandfather was gruff, barking stern orders and hardly smiling.

The definition for pretentious is "Making unjustified claims." Used in a sentence: The pretentious boy said that he was the fastest runner, but he finished last in the race.

The definition for rail is "To scold in harsh language." Used in a sentence: Clay began to cry as his irate manager railed at him for missing the deadline.

The definition for repel is "To resist, reject." Used in a sentence: The soldiers made a massive charge to repel the invaders.