fog vs ice fog

fog and ice fog both are nouns.

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

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

Other hyponyms of fog include fogbank, pogonip, mist, pea-souper, pea soup.

fog (noun)	ice fog (noun)
confusion characterized by lack of clarity	a dense winter fog containing ice particles
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

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