Crimson or maroon (3)
I believe the answer is:
red
I believe this clue is a double definition.
'crimson' is the first definition.
(I know that crimson can be written as red)
'maroon' is the second definition.
(I've seen this in another clue)
(Other definitions for red that I've seen before include "Inflamed" , "Scarlet or vermilion" , "Warning light colour" , "Primary colour" , "Bordeaux claret, for instance" .)