adverb

without doubt (used for emphasis).

I shall definitely be at the airport to meet you

certainly,surely,for sure,unquestionably,without/beyond doubt,without/beyond question,beyond any doubt,undoubtedly,indubitably,assuredly,positively,absolutely,undeniably,irrefutably,incontrovertibly,incontestably,unmistakably,plainly,clearly,obviously,patently,palpably,transparently,categorically,decidedly,unequivocally,easily,far and away,by a mile,without fail,there are no two ways about it,there’s no denying it,needless to say,as sure as eggs is eggs