Wiktionary
undoubtably
adv. (context sometimes considered nonstandard English) Without doubt; indubitably, undoubtedly.
Usage examples of "undoubtably".
It was inches-thick solid steel, with no visible lock mechanism, and undoubtably booby-trapped in a dozen ways, from hidden disrupters to primed explosives.
Undoubtably, Leng selected victims that would not be missed: street urchins, workhouse boys and girls.