First-class and Rad

First-class adjective - Of the very best kind.

Rad and first-class are semantically related In some cases you can use "Rad" instead an adjective phrase "First-class".

Rad noun - A unit of absorbed ionizing radiation equal to 100 ergs per gram of irradiated material.

First-class and rad are semantically related in good topic. Sometimes you can use "First-class" instead an adjective "Rad", if it concerns topics such as pleasant, amazing.