Definition of exploit

Malicious code that takes advantage of vulnerabilities in other software in order to take unwanted and unexpected action on impacted systems. An exploit is often used to install other malicious or potentially unwanted software on a target computer without the knowledge or consent of the affected user.

an attack on a computer system, especially one that takes advantage of a particular vulnerability that the system offers to intruders. Used as a verb, the term refers to the act of successfully making such an attack.