The definition for appraise is "To evaluate the worth of." Used in a sentence: Simone, an expert in African sculpture, was asked to appraise the ambassador's collection of masks.

The definition for dubious is "Questionable." Used in a sentence: Karl found Kevin's claim that he was sick dubious, as he had just seen him playing football.

The definition for mediate is "To come between parties in order to reconcile." Used in a sentence: The diplomatic Henry was able to mediate between the quarreling sisters.

The definition for penurious is "Extrememly stingy." Used in a sentence: Ebenezer Scrooge was most penurious, refusing to give even a penny to charity.

The definition for ploy is "A contrived plan." Used in a sentence: Sarah thought George's ploy of borrowing her notes was a cowardly way to ask her out.