thickheaded vs blockheaded

thickheaded and blockheaded both are adjectives.

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

As adjectives, thickheaded and blockheaded are synonyms defined as:

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

thickheaded (adjective)	blockheaded (adjective)
(used informally) stupid	(used informally) stupid