shack vs igloo

shack and igloo both are nouns.

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

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

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

Other hyponyms of shack include iglu, mudhif.

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

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