IPA: /ʌnˈwɜːrkəbl/
KK: /ʌnˈwɜrkəbl/
Not able to be used or put into practice successfully; impractical.
The plan was deemed unworkable due to its high costs and complexity.
Unworkable → It is formed from "un-" (meaning not) and "workable" (from "work" (from Old English *weorc*, meaning to perform or act) and "-able" (meaning capable of)). The word "unworkable" means not capable of being worked or performed.
Think of 'not' ('un-') being added to 'capable of working' ('workable') — that's why unworkable means something that cannot be worked.