Certainly

• POS: Adverb
• HYPHEN: cer=tain=ly

CIDE DICTIONARY

Certainly, adv. 

 Without doubt or question; unquestionably.  [1913 Webster]

OXFORD DICTIONARY

Certainly, adv.
1 undoubtedly, definitely.
2 confidently.
3 (in affirmative answer to a question or command) yes; by all means.

THESAURUS

Certainly

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, demonstrably, distinctly, exactly, factually, fatefully, fine, for a certainty, for a fact, for certain, for real, for sure, forsooth, good, good enough, hear, historically, in all conscience, in fact, in reality, in truth, in very sooth, indeed, indeedy, indefeasibly, indubitably, ineluctably, inescapably, inevasibly, inevitably, inexorably, inflexibly, irrevocably, ja, just so, mais oui, manifestly, most assuredly, most certainly, naturally, naturellement, necessarily, nothing else but, noticeably, observably, obviously, of a truth, of course, okay, oui, patently, positively, precisely, quite, rather, really, really-truly, relentlessly, right, righto, sensibly, seriously, sure, sure thing, surely, to a certainty, to be sure, truly, unambiguously, unavoidably, uncontrollably, undeniably, undoubtedly, unequivocally, unmistakably, unpreventably, unyieldingly, verily, veritably, very well, visibly, well and good, why yes, with truth, without doubt, yea, yeah, yep, yes, yes indeed, yes indeedy, yes sir, yes sirree

ROGET THESAURUS

Certainly

Certainty

N certainty, necessity, certitude, surety, assurance, dead certainty, moral certainty, infallibleness, infallibility, reliability, indubitableness, inevitableness, unquestionableness, gospel, scripture, church, pope, court of final appeal, res judicata, ultimatum positiveness, dogmatism, dogmatist, dogmatizer, doctrinaire, bigot, opinionist, Sir Oracle, ipse dixit, fact, positive fact, matter of fact, fait accompli, certain, sure, assured, solid, well-founded, unqualified, absolute, positive, determinate, definite, clear, unequivocal, categorical, unmistakable, decisive, decided, ascertained, inevitable, unavoidable, avoidless, ineluctable, unerring, infallible, unchangeable, to be depended on, trustworthy, reliable, bound, unimpeachable, undeniable, unquestionable, indisputable, incontestable, incontrovertible, indubitable, irrefutable, conclusive, without power of appeal, indubious, without doubt, beyond a doubt, without a shade or shadow of doubt, without question, beyond question, past dispute, clear as day, beyond all question, beyond all dispute, undoubted, uncontested, unquestioned, undisputed, questionless, doubtless, authoritative, authentic, official, sure as fate, sure as death and taxes, sure as a gun, evident, self-evident, axiomatic, clear, clear as day, clear as the sun at noonday, certainly, for certain, certes, sure, no doubt, doubtless, and no mistake, flagrante delicto, sure enough, to be sure, of course, as a matter of course, a coup sur, to a certainty, in truth, at any rate, at all events, without fail, coute que coute, coute qu'il coute, whatever may happen, if the worst come to the worst, come what may, happen what may, come what will, sink or swim, rain or shine, cela va sans dire, there is no question, no question, not a shadow of doubt, there is not a shadow of doubt, the die is cast, facts are stubborn things.

Assent

N assent, assentment, acquiescence, admission, nod, accord, concord, concordance, agreement, affirmance, affirmation, recognition, acknowledgment, avowal, confession of faith, unanimity, common consent, consensus, acclamation, chorus, vox populi, popular belief, current belief, current opinion, public opinion, concurrence, cooperation, ratification, confirmation, corroboration, approval, acceptance, visa, indorsement, consent, pressure to conform, herd instinct, peer pressure, assenting, of one accord, of one mind, of the same mind, at one with, agreed, acquiescent, content, willing, uncontradicted, unchallenged, unquestioned, uncontroverted, carried, agreed, nem, con, nemine contradicente unanimous, agreed on all hands, carried by acclamation, affirmative, yes, yea, ay, aye, true, good, well, very well, very true, well and good, granted, even so, just so, to be sure, 'thou hast said', you said it, you said a mouthful, truly, exactly, precisely, that's just it, indeed, certainly, you bet, certes, ex concesso, of course, unquestionably, assuredly, no doubt, doubtless, naturally, natch, be it so, so be it, so let it be, amen, willingly, affirmatively, in the affirmative, OK, all right, might as well, why not? with one consent, with one voice, with one accord, unanimously, una voce, by common consent, in chorus, to a man, nem, con, nemine contradicente, nemine dissentiente, without a dissentient voice, as one man, one and all, on all hands, avec plaisir, chi tace accousente, the public mind is the creation of the Master-Writ, you bet your sweet ass it is, what are we waiting for? whenever you're ready, anytime you're ready.

Truth

N truth, fact, reality, plain fact, plain matter of fact, nature, truth, verity, gospel, gospel truth, God's honest truth, orthodoxy, authenticity, veracity, correctness, correctitude, accuracy, exactitude, exactness, preciseness, precision, delicacy, rigor, mathematical precision, punctuality, clockwork precision, conformity to rule, nicety, orthology, ipsissima verba, realism, plain truth, honest truth, sober truth, naked truth, unalloyed truth, unqualified truth, stern truth, exact truth, intrinsic truth, nuda veritas, the very thing, not an illusion, real Simon Pure, unvarnished tale, unvarnished truth, the truth the whole truth and nothing but the trut, just the thing, real, actual, veritable, true, right, correct, certain, substantially true, categorically true, definitively true, true to the letter, true as gospel, unimpeachable, veracious, unreconfuted, unconfuted, unideal, unimagined, realistic, exact, accurate, definite, precise, well-defined, just, just so, so, strict, severe, close, literal, rigid, rigorous, scrupulous, religiously exact, punctual, mathematical, scientific, faithful, constant, unerring, curious, particular, nice, delicate, fine, clean-cut, clear-cut, verified, empirically true, experimentally verified, substantiated, proven (demonstrated), rigorously true, unquestionably true, true by definition, genuine, authentic, legitimate, orthodox, official, ex officio, pure, natural, sound, sterling, unsophisticated, unadulterated, unvarnished, unalloyed, uncolored, in its true colors, pukka, well-grounded, well founded, solid, substantial, tangible, valid, undistorted, undisguised, unaffected, unexaggerated, unromantic, unflattering, truly, verily, indeed, really, in reality, with truth, certainly, actually, in effect, exactly, ad amussim, verbatim, verbatim et literatim, word for word, literally, literatim, totidem vervis, sic, to the letter, chapter and verse, ipsissimis verbis, ad unguem, to an inch, to a nicety, to a hair, to a tittle, to a turn, to a T, au pied de la lettre, neither more nor less, in every respect, in all respects, sous tous les rapports, at any rate, at all events, strictly speaking, the truth is, the fact is, rem acu tetigisti, en suivant la verite, ex facto jus oritur, la verita e figlia del empo, locos y ninos dicen la verdad, crazy people and children tell the truth, nihil est veritatis luce dulcius, veritas nunquam perit, veritatem dies aperit, the truth, the whole truth, and nothing but the truth, just the facts, ma'am, just the facts.