What Does Payload Mean?
A payload refers to the component of a computer virus that executes a malicious activity. Apart from the speed in which a virus spreads, the threat level of a virus is calculated by the damages it causes. Viruses with more powerful payloads tend to be more harmful.
Techopedia Explains Payload
Some viruses just copy themselves from one computer to other. Other viruses may steal data or files, permit eavesdropping or unauthorized access, destroy data and cause other consequences. It is also possible for a virus to carry multiple payloads.