augment
The definition for augment is "To make greater." Used in a sentence: Wanda read the dictionary every night to augment her vocabulary.
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.
inviolable
The definition for inviolable is "Secure from assault of trespass." Used in a sentence: Situated on a mountain, with sixteen–foot walls, the castle was inviolable.
mandate
The definition for mandate is "An official order or commission to do something." Used in a sentence: Martha reluctantly obeyed the mandate to vacate her apartment.
rancorous
The definition for rancorous is "Marked by deep ill–will." Used in a sentence: The rancorous competition between the two chess clubs actually ended in a brawl.