ice fog vs fog

ice fog and fog both are nouns.

Word	Noun	Adjective	Verb	Adverb
ice fog	Yes	No	No	No
fog	Yes	No	Yes	No

As nouns, fog is a hypernym of ice fog; that is, fog is a word with a broader meaning than ice fog:

ice fog (noun)	fog (noun)
a dense winter fog containing ice particles	confusion characterized by lack of clarity
	droplets of water vapor suspended in the air near the ground
	an atmosphere in which visibility is reduced because of a cloud of some substance

ice fog (verb)	fog (verb)
	make less visible or unclear