irrecusable
adjective
ir·re·cu·sa·ble ˌir-i-ˈkyü-zə-bəl 
: not subject to exception or rejection
irrecusable proof
irrecusably
ˌir-i-ˈkyü-zə-blē
adverb 
Word History
Etymology
Late Latin irrecusabilis, from Latin in- + recusare to reject, refuse — more at recusant
First Known Use
1776, in the meaning defined above