thickheaded vs loggerheaded

thickheaded and loggerheaded both are adjectives.

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

As adjectives, thickheaded and loggerheaded are synonyms defined as:

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

thickheaded (adjective)	loggerheaded (adjective)
(used informally) stupid	(used informally) stupid