1 - Easy
2 - Moderate
3 - Hard
4 - Very Hard
5 - All Out
You don’t need to know what a workout should “feel” like. This is just how it felt for you. You might have an aerobic ride feel very hard because you’re thrashed, or you might have a vo2 ride feel moderate because you’re more fit than that level.
The idea is to not have anyone know what a ride should feel like relative to the workout. They just say on 1-5 how hard it was.