saphead vs muggins

saphead and muggins both are nouns.

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

As nouns, saphead and muggins are synonyms defined as:

Other synonyms of saphead include fool, sap, tomfool.

saphead (noun)	muggins (noun)
a person who lacks good judgment	a person who lacks good judgment