tenacious vs dour

tenacious and dour both are adjectives.

Word	Noun	Adjective	Verb	Adverb
tenacious	No	Yes	No	No
dour	No	Yes	No	No

As adjectives, tenacious and dour are synonyms defined as:

Other synonyms of tenacious include dogged, persistent, pertinacious, unyielding.

tenacious (adjective)	dour (adjective)
good at remembering	showing a brooding ill humor
sticking together	stubbornly unyielding
stubbornly unyielding	harshly uninviting or formidable in manner or appearance