Is Redheadedness a Word?

Is red-headed one word?

A redhead is a person with red hair. Although sometimes it looks more like orange, “orangehead” isn't a thing. ... The word redhead has been used to mean someone with red hair since at least the 13th century.

Is there a hyphen in red-haired?

2) He is a cute red-haired little boy. But he is not a red boy; he is a 'red-haired boy'. Those two words work together to describe the boy, so they have to be joined with a hyphen.