Intransigence means unwillingness to change one's views or to agree on a compromise; stubbornness. 'Uncompromising' is the correct synonym - someone who refuses to make concessions. 'Uninteresting' means boring, 'unprincipled' means lacking morals, and 'unscrupulous' means dishonest or unethical - none of these capture the sense of stubborn refusal to yield.