Huge without third colour (3)
I believe the answer is:
hue
'colour' is the definition.
(I've seen this before)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for hue that I've seen before include "Shade, aspect; Vietnam port" , "appearance" , "complexion" , "Tone, shade" , "Tinge" .)