steatopygia vs blubber

steatopygia and blubber both are nouns.

Word	Noun	Adjective	Verb	Adverb
steatopygia	Yes	No	No	No
blubber	Yes	No	Yes	No

As nouns, blubber is a hypernym of steatopygia; that is, blubber is a word with a broader meaning than steatopygia:

Other hypernyms of steatopygia include avoirdupois, fat, fatness.

steatopygia (noun)	blubber (noun)
an extreme accumulation of fat on the buttocks	excess bodily weight
	an insulating layer of fat under the skin of whales and other large marine mammals; used as a source of oil

steatopygia (verb)	blubber (verb)
	cry or whine with snuffling
	utter while crying