mob vs youth gang

mob and youth gang both are nouns.

Word	Noun	Adjective	Verb	Adverb
mob	Yes	No	Yes	No
youth gang	Yes	No	No	No

As nouns, youth gang is a hyponym of mob; that is, youth gang is a word with a more specific, narrower meaning than mob:

Other hyponyms of mob include nest.

mob (noun)	youth gang (noun)
a disorderly crowd of people	a gang whose members are teenagers
an association of criminals
a loose affiliation of gangsters in charge of organized criminal activities

mob (verb)	youth gang (verb)
press tightly together or cram