The term 'Improper Usage' refers to instances where individuals use system resources in a manner that is not compliant with the organization's acceptable usage policies. This could involve a range of activities, from excessive personal use of the internet during work hours to the installation of unauthorized software. It is differentiated from 'Unauthorized Access,' which implies gaining access to resources one is not permitted to use, and 'Malicious Code,' which relates to software designed to harm or exploit systems. 'Denial-of-Service' refers to attacks intended to disrupt service availability.