How does no day malware vary from standard malware?

Absolutely no day malware, also known as zero hour malware or absolutely no day attacks, is a type of malware that benefits from a previously unidentified software vulnerability. Attackers who are able to exploit these vulnerabilities can acquire access to a system or network without any detection. This makes zero day malware a severe risk to services and people alike.

imp source Standard malware, on the other hand, is malware that is widely known and has been around for a long time. Standard malware can still be unsafe, it is not as stealthy or tough to detect as absolutely no day malware.