If you are lion-hearted, you are very brave — as if you had the heart of a lion. People use it as praise. It feels a little old and a little grand: more at home in stories, speeches, and nicknames than in everyday chat. You might call a firefighter lion-hearted, or a child who speaks up when they are scared. It does not mean you are angry or wild like a lion. It is about courage, not about roaring. The colour of the word still comes from names like Richard the Lionheart: brave on purpose, not just loud.