combustion
The definition for combustion is "Act of burning." Used in a sentence: Campers must use fire with great caution to prevent combustion of the parched brush.
derivative
The definition for derivative is "Lacking originality." Used in a sentence: Critics panned the movie as a derivative version of last year's Best Picture.
ethical
The definition for ethical is "Conforming to accepted standards." Used in a sentence: Mary did the ethical thing and turned in the diamond necklace she found.
exception
The definition for exception is "A case to which the rule does not apply." Used in a sentence: The teacher made an exception and let Gina eat her snack in class.
prune
The definition for prune is "To reduce by removing excess." Used in a sentence: The candidate pruned his speech so he would not exceed the time limit.