Englishundoubtedly
adverb
they are undoubtedly guilty:
doubtless, indubitably, doubtlessly, no doubt, without (a) doubt, beyond (a) doubt, beyond the shadow of a doubt;
unquestionably, beyond question, indisputably, undeniably, incontrovertibly, irrefutably;
unequivocally, clearly, plainly, obviously, patently, positively, absolutely, certainly, with certainty;
decidedly, definitely, surely, assuredly, of course, indeed.
▷antonyms possibly.