incontestablement bedeutet auf Englisch

undeniably▼◼◼◼(in an undeniable manner)
adverb
[UK: ˌʌn.dɪ.ˈnaɪə.bli] [US: ˌʌn.də.ˈnaɪə.bli]

incontrovertibly▼◼◼◻(in incontrovertible manner)
adverb
[UK: incontro.vert.i.bi] [US: incontro.ver.ti.bi]