- certainly as a adverb:
Definitely or positively (`sure' is sometimes used informally for `surely'):
— She certainly is a hard worker.
Roget 474: certainly etc. adj.; for certain, certes [Lat.], sure, no doubt, doubtless, and no mistake, flagrante delicto [Lat.], sure enough, to be sure, of course, as a matter of course, ... show more
Moby thesaurus: OK, Roger, absolutely, actually, all right, alright, alrighty, amen, and no mistake, as you say, assuredly, at all events, at any rate, aye, by all means, clearly, da, decidedly, decisively, definitely ... show more.
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