sobbing vs tears

sobbing and tears both are nouns.

Word	Noun	Adjective	Verb	Adverb
sobbing	Yes	No	No	No
tears	Yes	No	No	No

As nouns, tears is a hypernym of sobbing; that is, tears is a word with a broader meaning than sobbing:

sobbing: convulsive gasp made while weeping
tears: the process of shedding tears (usually accompanied by sobs or other inarticulate sounds)

Other hypernyms of sobbing include crying, weeping.

sobbing (noun)	tears (noun)
convulsive gasp made while weeping	the process of shedding tears (usually accompanied by sobs or other inarticulate sounds)