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 egotist is "Self–important person." Used in a sentence: Darren dreaded carpooling with the egotist Shelly, who talked about herself nonstop.

The definition for incidental is "Minor." Used in a sentence: The accountant advised Justine not to report her incidental expenses.

The definition for naive is "Lacking worldy wisdom." Used in a sentence: The naive Simon assumed that everyone was as simple and kind as he was.

The definition for rehash is "To discuss again." Used in a sentence: "Sandra," said her mother, "I am tired of rehashing this same topic over and over."