colour vs colouration

colour and colouration both are nouns.

Word	Noun	Adjective	Verb	Adverb
colour	Yes	Yes	Yes	No
colouration	Yes	No	No	No

As nouns, colouration is a hyponym of colour; that is, colouration is a word with a more specific, narrower meaning than colour:

colour: a visual attribute of things that results from the light they emit or transmit or reflect
colouration: appearance with regard to color

As nouns, colour and colouration are synonyms defined as:

Other synonyms of colour include color, coloration.

colour (noun)	colouration (noun)
a visual attribute of things that results from the light they emit or transmit or reflect	choice and use of colors (as by an artist)
the appearance of objects (or light sources) described in terms of a person's perception of their hue and lightness (or brightness) and saturation	appearance with regard to color
the timbre of a musical sound	the timbre of a musical sound
interest and variety and intensity
an outward or token appearance or form that is deliberately misleading
(physics) the characteristic of quarks that determines their role in the strong interaction
any material used for its color

colour (adjective)	colouration (adjective)
having or capable of producing colors

colour (verb)	colouration (verb)
change color, often in an undesired manner
add color to
affect as in thought or feeling
give a deceptive explanation or excuse for
decorate with colors
modify or bias