IPA: //ʌnˈbɪldəbl//
KK: /ʌnˈbɪldəbl/
Not able to be constructed or built on due to certain limitations or conditions.
The area was declared unbuildable because of its unstable soil.
Unbuildable → It is formed from "un-" (meaning not) and "build" (from Old English "byldan", meaning to construct or create) and "-able" (meaning capable of). The word "unbuildable" means not capable of being constructed or created.
Think of 'not' ('un-') being added to 'build' — this helps you remember that 'unbuildable' means something that cannot be constructed.