Sixth colour in a rainbow (6)

I believe the answer is:

indigo

(Other definitions for indigo that I've seen before include "Ellington's Mood" , "Spectral colour" , "A deep blue dye or colour" , "Violet-blue dye" , "Blue-violet colour" .)

I've seen this clue in The Guardian.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.