scallywag vs youngster

scallywag and youngster both are nouns.

Word	Noun	Adjective	Verb	Adverb
scallywag	Yes	No	No	No
youngster	Yes	No	No	No

As nouns, youngster is a hypernym of scallywag; that is, youngster is a word with a broader meaning than scallywag:

Other hypernyms of scallywag include child, fry, kid, minor, nestling, nipper, shaver, small fry, tiddler, tike, tyke.

scallywag (noun)	youngster (noun)
one who is playfully mischievous	a young person of either sex
a deceitful and unreliable scoundrel
a white Southerner who supported Reconstruction policies after the American Civil War (usually for self-interest)