sea squab vs fugu

sea squab and fugu both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea squab	Yes	No	No	No
fugu	Yes	No	No	No

As nouns, fugu is a hyponym of sea squab; that is, fugu is a word with a more specific, narrower meaning than sea squab:

sea squab: delicacy that is highly dangerous because of a potent nerve poison in ovaries and liver
fugu: a blowfish highly prized as a delicacy in Japan but highly dangerous because the skin and organs are poisonous

sea squab (noun)	fugu (noun)
delicacy that is highly dangerous because of a potent nerve poison in ovaries and liver	a blowfish highly prized as a delicacy in Japan but highly dangerous because the skin and organs are poisonous