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 drub is "To defeat decisively." Used in a sentence: The powerful young boxer drubbed the longtime champion.

The definition for impenitent is "Lacking remorse." Used in a sentence: The impenitent criminal received a harsh penalty, but his remorseful accomplice was released.

The definition for promote is "To contribute to the growth or prosperity of." Used in a sentence: The promote peace, the diplomat hosted a talk between the warring nations.

The definition for untenable is "Not able to be defended." Used in a sentence: Rashid made the untenable statement that George Washington was the second president of the United States.