human head vs noggin

human head and noggin both are nouns.

Word	Noun	Adjective	Verb	Adverb
human head	Yes	No	No	No
noggin	Yes	No	No	No

As nouns, noggin is a hyponym of human head; that is, noggin is a word with a more specific, narrower meaning than human head:

Other hyponyms of human head include bullethead, attic, bean, bonce, dome, noodle.

human head (noun)	noggin (noun)
the head of a human being	informal terms for a human head