British spelling vs sombre

British spelling is a noun but sombre is not a noun.

Word	Noun	Adjective	Verb	Adverb
British spelling	Yes	No	No	No
sombre	No	Yes	No	No

British spelling (noun)	sombre (noun)
English orthography used in the UK, Ireland and most of the Commonwealth (characterized by 'analyse', 'centre' and 'useable')

British spelling (adjective)	sombre (adjective)
	lacking brightness or color; dull
	grave or even gloomy in character