Insouciant - free from concern, worry, or anxiety. Origin Insouciant entered English from French, based on the French verb soucier meaning "to worry." Ultimately it finds its roots in the Latin sollicitāre meaning "to disturb."
The color amaranthine came from the Greek word ‘amarantos’ which meant unfading. The word Amaranth was used to name an imaginary, undying flower that was, presumably, a deep red-purple color and there you have the two uses of the word today. Lovely stuff.