color of law vs colour of law

color of law and colour of law both are nouns.

Word	Noun	Adjective	Verb	Adverb
color of law	Yes	No	No	No
colour of law	Yes	No	No	No

As nouns, color of law and colour of law are synonyms defined as:

color of law and colour of law: a mere semblance of legal right; something done with the apparent authority of law but actually in contravention of law

color of law (noun)	colour of law (noun)
a mere semblance of legal right; something done with the apparent authority of law but actually in contravention of law	a mere semblance of legal right; something done with the apparent authority of law but actually in contravention of law