gob vs oral cavity

gob and oral cavity both are nouns.

Word	Noun	Adjective	Verb	Adverb
gob	Yes	No	No	No
oral cavity	Yes	No	No	No

As nouns, oral cavity is a hypernym of gob; that is, oral cavity is a word with a broader meaning than gob:

gob: informal terms for the mouth
oral cavity: the opening through which food is taken in and vocalizations emerge

Other hypernyms of gob include mouth, oral fissure, rima oris.

gob (noun)	oral cavity (noun)
informal terms for the mouth	the opening through which food is taken in and vocalizations emerge
a lump of slimy stuff
a man who serves as a sailor