unyielding vs pertinacious

unyielding and pertinacious both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unyielding	No	Yes	No	No
pertinacious	No	Yes	No	No

As adjectives, unyielding and pertinacious are synonyms defined as:

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

unyielding (adjective)	pertinacious (adjective)
resistant to physical force or pressure	stubbornly unyielding
stubbornly unyielding