beneficial
The definition for beneficial is "Helpful." Used in a sentence: there is no doubt that eating vegetables is beneficial to one's health.
fidelity
The definition for fidelity is "State of being faithful." Used in a sentence: Unlike her fickle friend Benji, May Belle was known for her fidelity.
insolence
The definition for insolence is "Boldness or rudeness." Used in a sentence: The boy's insolence to the policeman embarrassed his mother.
lurid
The definition for lurid is "Causing horror, shocking." Used in a sentence: The lurid photos of the crime scene upset the jury.
rail
The definition for rail is "To scold in harsh language." Used in a sentence: Clay began to cry as his irate manager railed at him for missing the deadline.