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 facade is "false or superficial appearance." Used in a sentence: Emily's smile is just a facade masking her broken heart.

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

The definition for parity is "Equality." Used in a sentence: Hilda, to avoid squabbles, aimed for parity in the slices of birthday cake.