tarnish vs blob

tarnish and blob both are nouns.

Word	Noun	Adjective	Verb	Adverb
tarnish	Yes	No	Yes	No
blob	Yes	No	Yes	No

As verbs, blob is a hypernym of tarnish; that is, blob is a word with a broader meaning than tarnish:

tarnish: make dirty or spotty, as by exposure to air; also used metaphorically
blob: make a spot or mark onto

Other hypernyms of tarnish include blot, fleck, spot.

tarnish (noun)	blob (noun)
discoloration of metal surface caused by oxidation	an indistinct shapeless form

tarnish (verb)	blob (verb)
make dirty or spotty, as by exposure to air; also used metaphorically	make a spot or mark onto