beneficial
The definition for beneficial is "Helpful." Used in a sentence: there is no doubt that eating vegetables is beneficial to one's health.
disdain
The definition for disdain is "Feeling of contempt." Used in a sentence: The arrogant writer did not hide his disdain for his uneducated dinner companion.
insolence
The definition for insolence is "Boldness or rudeness." Used in a sentence: The boy's insolence to the policeman embarrassed his mother.
stealth
The definition for stealth is "The act of moving secretly or unnoticed." Used in a sentence: The burglar took the ring by stealth, slipping it from the sleeping woman's finger.
unscrupulous
The definition for unscrupulous is "Lacking principles." Used in a sentence: The unscrupulous salesman was fired for lying to his customers.