beneficial
The definition for beneficial is "Helpful." Used in a sentence: there is no doubt that eating vegetables is beneficial to one's health.
brandish
The definition for brandish is "To shake or wave menacingly." Used in a sentence: The baseball player was fined for brandishing his bat at the opposing pitcher.
garish
The definition for garish is "Offensively bright." Used in a sentence: The garish wallpaper offended Jerome, who preferred subtle colors.
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.
rehash
The definition for rehash is "To discuss again." Used in a sentence: "Sandra," said her mother, "I am tired of rehashing this same topic over and over."