igloo vs shack

igloo and shack both are nouns.

Word	Noun	Adjective	Verb	Adverb
igloo	Yes	No	No	No
shack	Yes	No	Yes	No

As nouns, shack is a hypernym of igloo; that is, shack is a word with a broader meaning than igloo:

igloo: an Eskimo hut; usually built of blocks (of sod or snow) in the shape of a dome
shack: small crude shelter used as a dwelling

Other hypernyms of igloo include hovel, hut, hutch, shanty.

igloo (noun)	shack (noun)
an Eskimo hut; usually built of blocks (of sod or snow) in the shape of a dome	small crude shelter used as a dwelling

igloo (verb)	shack (verb)
	move, proceed, or walk draggingly or slowly
	make one's home in a particular place or community