dour vs tenacious

dour and tenacious both are adjectives.

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

As adjectives, dour and tenacious are synonyms defined as:

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

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