beneficial
The definition for beneficial is "Helpful." Used in a sentence: there is no doubt that eating vegetables is beneficial to one's health.
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.
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.
exalt
The definition for exalt is "To elevate by praise." Used in a sentence: The fireman was publicly exalted for his heroism.
obnoxious
The definition for obnoxious is "Highly offensive." Used in a sentence: The manager asked the obnoxious diner to leave the restaurant.