clouding up vs vapour

clouding up and vapour both are nouns.

Word	Noun	Adjective	Verb	Adverb
clouding up	Yes	No	No	No
vapour	Yes	No	No	No

As nouns, vapour is a hypernym of clouding up; that is, vapour is a word with a broader meaning than clouding up:

Other hypernyms of clouding up include evaporation, vapor, vaporisation, vaporization.

clouding up (noun)	vapour (noun)
the process whereby water particles become visible in the sky	the process of becoming a vapor
	a visible suspension in the air of particles of some substance