goofball vs saphead

goofball and saphead both are nouns.

Word	Noun	Adjective	Verb	Adverb
goofball	Yes	No	No	No
saphead	Yes	No	No	No

As nouns, saphead is a hypernym of goofball; that is, saphead is a word with a broader meaning than goofball:

Other hypernyms of goofball include fool, muggins, sap, tomfool.

goofball (noun)	saphead (noun)
a man who is a stupid incompetent fool	a person who lacks good judgment
a person who amuses others by ridiculous behavior