dubious
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.
flagrant
The definition for flagrant is "Noticeably offensive." Used in a sentence: The executive was fired for his flagrant abuse of the company expense account.
incisive
The definition for incisive is "Impressively direct and decisive." Used in a sentence: Samir's incisive leadership made him the natural choice for president of the company.
mediate
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.
preclude
The definition for preclude is "To rule out in advance." Used in a sentence: "Having cake now will preclude dessert later," said Amber's mother.