ad. 不容置疑地, 明确地, 无疑地

[ adv ]
in a manner or to a degree that could not be doubted
<adv.all>
it was immediately and indubitably apparent that I had interrupted a scene of lovershis guilt was established beyond a shadow of a doubt

Indubitably \In*du"bi*ta*bly\, adv.
Undoubtedly; unquestionably; in a manner to remove all doubt.

Oracles indubitably clear and infallibly certain.
--Barrow.