futile
The definition for futile is "Without purpose, completely ineffective." Used in a sentence: Arguing with Andrew is futile because he never changes his mind.
incumbent
The definition for incumbent is "Necessary as a duty or responsibility." Used in a sentence: It was incumbent on Jack to attend his father's retirement party.
indecorous
The definition for indecorous is "In bad taste." Used in a sentence: My parents banned Chad from our house because of his indecorous behavior at dinner.
ploy
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.
regale
The definition for regale is "To amuse." Used in a sentence: My clever brother Jeffrey regaled the dinner guests with tales of his adventures.