fatheaded vs loggerheaded

fatheaded and loggerheaded both are adjectives.

Word	Noun	Adjective	Verb	Adverb
fatheaded	No	Yes	No	No
loggerheaded	No	Yes	No	No

As adjectives, fatheaded and loggerheaded are synonyms defined as:

Other synonyms of fatheaded include blockheaded, boneheaded, duncical, duncish, thick-skulled, thick, thickheaded, wooden-headed.

fatheaded (adjective)	loggerheaded (adjective)
(used informally) stupid	(used informally) stupid