This term has come from an interesting book by Kim Scott, of the same name. It promotes the idea of telling people actually what you are thinking. It helps you to challenge people, especially people that you work with, rather than forgetting about an issue that is important.
So, with radical candour, you are saying what you think, though being careful about it, and therefore caring about the person and how they are taking the feedback.
The book says that when you are managing someone or coaching them, if you want to help someone, sometimes you should directly point out where they can improve how they are doing things. Otherwise they will never receive that constructive feedback. However, of course people can be really sensitive about this, so you have to do this in a way that really saves face for them. This uses all the skills of emotional intelligence, in knowing the right moment and the best way to do this.
This reminds me of a talk I heard once, directed at NHS Consultant doctors, about giving feedback to junior doctors about how they are progressing in their training. It’s about being very specific in the feedback, giving it in small quantities and making sure it is timely.
To not give someone feedback, when they really need it, is to be what Scott calls ‘ruinously empathetic’. This is to let them continue on with making the same mistakes and for them to never know where they stand, whether they are doing a good job or not.
So, think about radical candor, when you are a boss or are coaching someone, if you see or hear something that needs challenging. After a bit of planning and practice, applying radical candour is not as difficult as you might think.