Synonyms of certainly in English:

certainly


See definition of certainly

adverb

1‘this is certainly a late work’

SYNONYMS
unquestionably, surely, assuredly, definitely, beyond question, without question, beyond doubt, unequivocally, indubitably, undeniably, irrefutably, indisputably, incontrovertibly, incontestably, obviously, patently, manifestly, evidently, plainly, clearly, transparently, palpably, unmistakably, conclusively, undisputedly, undoubtedly
there are no two ways about it
informal as sure as eggs is eggs
ANTONYMS

possibly

2‘our revenues are certainly lower than anticipated’

SYNONYMS
admittedly, beyond question, without question, definitely, undoubtedly, without a doubt

exclamation

1‘‘And now, shall we clean the diamonds?’ ‘Certainly.’’

SYNONYMS
yes, definitely, absolutely, sure, by all means, quite, indeed, of course, positively, naturally, without doubt, without question, unquestionably
affirmative
British dated rather
ANTONYMS

no, possibly