How do you define racism?

I don’t mean what groups. For this Q race is a broad term that will refer to any group. Black, Hispanic, white, Chinese, everyone counts.

What I am interested in is when do you label someone racist. If someone says racist things, but then meets every person as an individual and is happy to have a friend from the very race they stereotype or put down, is the person racist? Or, just uncouth?

If someone makes stereotypes about various groups, are they racist?

If they will be freinds with, but not consider marrying someone from another group, are they racist?

Whe do you draw the line? Any mention of race? Or, the other extreme, they need to be a card carrying KKK member?