squid vs giant squid

squid and giant squid both are nouns.

Word	Noun	Adjective	Verb	Adverb
squid	Yes	No	No	No
giant squid	Yes	No	No	No

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

squid: widely distributed fast-moving ten-armed cephalopod mollusk having a long tapered body with triangular tail fins
giant squid: largest mollusk known about but never seen (to 60 feet long)

Other hyponyms of squid include loligo, ommastrephes, architeuthis.

squid (noun)	giant squid (noun)
widely distributed fast-moving ten-armed cephalopod mollusk having a long tapered body with triangular tail fins	largest mollusk known about but never seen (to 60 feet long)
(Italian cuisine) squid prepared as food