polished C2+

/ˈpɑlɪʃt/ smooth and shiny from rubbing; refined and accomplished

unpolished C2+

/ʌnˈpɑlɪʃt/ not polished; lacking refinement or finish

interpolation C2+

/ɪnˌtɝpəˈleɪʃən/ the insertion of something extra, or estimation of values between known points