What is the definition of abuse

treat with cruelty or violence, especially regularly or repeatedly.

"riders who abuse their horses should be prosecuted

The improper usage or treatment of a thing, often to unfairly or improperly gain benefit. Abuse can come in many forms, such as physical or verbal maltreatment, injury, assault, violation, unjust practices, crimes, or other types of aggression.

Explanation:

answer; buying the bill at a discount from the face value to be received at maturity;