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.
gravity
The definition for gravity is "Importance, significance." Used in a sentence: Understanding the gravity of his error, Ken offered his humblest apology.
indecorous
The definition for indecorous is "In bad taste." Used in a sentence: My parents banned Chad from our house because of his indecorous behavior at dinner.
repel
The definition for repel is "To resist, reject." Used in a sentence: The soldiers made a massive charge to repel the invaders.