What does Keep It Simple Stupid Principle (KISS Principle) mean?

Principle: Simple

The “keep it simple stupid” (KISS) principle is a design rule. The rule states that systems perform best when they have simple designs. As opposed to complex designs. KISS is not meant to imply stupidity. These are usually intelligent systems thought to be stupid by their simple designs. The KISS Principle prevents creeping feature requirements and other IT issues.