Definition of unperceptable in English:

unperceptable

Pronunciation /(ˌ)ʌnpəˈsɛptəbl/

adjective

non standard, rare

Origin

Late 17th century; earliest use found in John Humfrey (bap. 1621, d. 1719), clergyman and ejected minister. From un- + classical Latin percept-, past participial stem of percipere perceive + -able.