incontrovertible(not capable of being denied, challenged, or disputed; closed to questioning) adjective [UK: ɪnˌk.ɒn.trə.ˈvɜː.təb.l̩] [US: ˌɪŋˌk.ɑːntro.ˈvɝː.təb.l̩]
undeniable(irrefutable, or impossible to deny) adjective [UK: ˌʌn.dɪ.ˈnaɪəb.l̩] [US: ˌʌn.də.ˈnaɪəb.l̩]