What is "unratable"

nontaxable \nontaxable\ adj. Not subject to taxation; -- of goods imported into a country or sold at retail outlets; as, most laws imposing sales taxes make food nontaxable. Opposite of taxable. [Narrower terms: duty-free; tax-exempt, tax-free; unratable; untaxed ] Also See: {exempt.

a. That cannot be rated.

adj. British; "unratable properties"