redheadednessEtymologyFrom redheaded + -ness; also, by surface analysis, red + headedness.redheadedness means the trait of having red hair on the head (in humans) or red feathers on the head (in birds). Lexicurio rates it Sui generis — a strength score of 87 out of 100.nounThe trait of having red hair on the head (in humans) or red feathers on the head (in birds).“The finding also suggests that redheadedness would have evolved separately in Neanderthals and humans, at different times and through different genetic variations.”