IPA: /ʌnˈmɪksəbl/
KK: /ʌnˈmɪksəbl/
Something that cannot be combined or blended together.
Oil and water are unmixable substances.
Unmixable → It is formed from "un-" (meaning not) and "mix" (from Latin "miscere", meaning to mix) and "-able" (meaning capable of). The word "unmixable" means not capable of being mixed together.
Think of something that is 'not' ('un-') able to be 'mixed' ('mix') — that's why unmixable means it cannot be mixed.