our eyes invent colors that aren’t even there “physically” in tbe true sense of the word. and colours are even cultural, so there is a lot of leeway with what a colour even is. even in genders there are differences in cultural colour perception.

non-spectral colours are very real: greyscale, pink, brown, and purple which are mixes of multiple wavelengths of light

then you have things like:

* green is blue (japan/china)

* homer’s wine dark sea

* colour word development which has some near-universal linguistic phenomenon where the start is light and dark words, then red, and there’s a list on and on.