An antivirus software is designed to detect, prevent, and remove malicious software or malware from a computer system. It operates by scanning files and programs for known patterns of malicious code or suspicious behavior. 

Here are some of the key features of an antivirus:

Scanning and detection: Antivirus software scans the system regularly to detect any malware that may have slipped through real-time protection.

Real-time protection: This feature scans files and programs as they are accessed or downloaded to prevent malware from infecting the system.

Quarantine: If a file or program is suspected of being infected, the antivirus software will quarantine it to prevent it from causing harm to the system.

Removal and cleanup: Once a virus has been detected, the antivirus software will attempt to remove it from the system and clean up any damage it may have caused.

Automatic updates: Antivirus software regularly updates its virus definitions and software to stay up-to-date with the latest threats and protect against them.

Overall, antivirus software is an essential tool in protecting computer systems from malware and keeping them running smoothly.