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 fraud is "Trick." Used in a sentence: The con man's fraud involved selling swampland to gullible investors.

The definition for implausible is "Unbelievable." Used in a sentence: Claudia's implausible excuse failed to convince her teacher.

The definition for lenient is "Mild or tolerant." Used in a sentence: The judge issued a lenient sentence because it was Frank's first offense.

The definition for redouble is "To make twice as great." Used in a sentence: As the sun began to set, Brittany redoubled her effort to find the necklace she had dropped in the field.