berserker vs Northman

berserker and Northman both are nouns.

Word	Noun	Adjective	Verb	Adverb
berserker	Yes	No	No	No
Northman	Yes	No	No	No

As nouns, Northman is a hypernym of berserker; that is, Northman is a word with a broader meaning than berserker:

berserker: one of the ancient Norse warriors legendary for working themselves into a frenzy before a battle and fighting with reckless savagery and insane fury
Northman: an inhabitant of Scandinavia

Other hypernyms of berserker include Norse, Scandinavian.

berserker (noun)	Northman (noun)
one of the ancient Norse warriors legendary for working themselves into a frenzy before a battle and fighting with reckless savagery and insane fury	an inhabitant of Scandinavia