Late Middle English (in an earlier sense). From un- + perceive + -able, in use as adjective perhaps after post-classical Latin imperceptibilisimperceptible.
Definition of unperceivable in US English:
unperceivable
adjective(ˌ)ʌnpəˈsiːvəbl
Imperceptible.
Origin
Late Middle English (in an earlier sense). From un- + perceive + -able, in use as adjective perhaps after post-classical Latin imperceptibilis imperceptible.