RichThesaurus
undoubtably
vs
unquestionably
undoubtably
adv
Without doubt; indubitably, undoubtedly.
unquestionably
adv
without question; beyond doubt; indubitably.
OK, right-on
How often have the words
undoubtably
and
unquestionably
occurred in a corpus of books?
(source:
Google Ngram Viewer
)