intransigent

in⋅tran⋅si⋅gent
   /ɪn'trænsɪdʒənt/ Show Spelled Pronunciation [in-tran-si-juhnt] Show IPA
-adjective
1.  refusing to agree or compromise; uncompromising; inflexible.
-noun
2.  a person who refuses to agree or compromise, as in politics.