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 interminable is "Never ending, or seemingly endless." Used in a sentence: The impatient Zoe found the longwinded lecture interminable.

The definition for negate is "To make invalid." Used in a sentence: Paula negated Tiffany's argument by proving that her main premise was false.

The definition for pretentious is "Making unjustified claims." Used in a sentence: The pretentious boy said that he was the fastest runner, but he finished last in the race.

The definition for rancorous is "Marked by deep ill–will." Used in a sentence: The rancorous competition between the two chess clubs actually ended in a brawl.