Word family noun doubt doubter adjective doubtful doubtless indubitable undoubted verb doubt adverb doubtfully indubitably undoubtedly
From Longman Dictionary of Contemporary Englishindubitablyin‧du‧bi‧ta‧bly /ɪnˈdjuːbətəbli $ ɪnˈduː-/ adverb formal TRUEcertainly or without doubt Mr Sachs is indubitably charming. —indubitable adjective 