tobacco juice vs spittle

tobacco juice and spittle both are nouns.

Word	Noun	Adjective	Verb	Adverb
tobacco juice	Yes	No	No	No
spittle	Yes	No	No	No

As nouns, spittle is a hypernym of tobacco juice; that is, spittle is a word with a broader meaning than tobacco juice:

tobacco juice: saliva colored brown by tobacco (snuff or chewing tobacco)
spittle: a clear liquid secreted into the mouth by the salivary glands and mucous glands of the mouth; moistens the mouth and starts the digestion of starches

Other hypernyms of tobacco juice include saliva, spit.

tobacco juice (noun)	spittle (noun)
saliva colored brown by tobacco (snuff or chewing tobacco)	a clear liquid secreted into the mouth by the salivary glands and mucous glands of the mouth; moistens the mouth and starts the digestion of starches