Synonyms for For certain:

• adj.

  •unmistakable (adjective)
  • indisputable,
  • glaring,
  • positive,
  • explicit,
  • clear,
  • conspicuous,
  • obvious,
  • plain,
  • patent,
  • pronounced,
  • straightforward,
  • transparent,
  • unambiguous,
  • manifest,
  • distinct,
  • apparent,
  • evident,
  • unequivocal,
  • palpable.
  •unquestionable (adjective)
  • flat,
  • true,
  • flawless,
  • irrefutable,
  • conclusive,
  • absolute,
  • genuine,
  • perfect,
  • dependable,
  • well-grounded,
  • incontrovertible,
  • incontestable,
  • real,
  • self-evident,
  • faultless,
  • downright,
  • certain,
  • undoubted,
  • superior,
  • unimpeachable,
  • cold,
  • authentic,
  • established,
  • veritable,
  • indubitable,
  • accurate,
  • bona fide,
  • undisputable,
  • reliable.

• adv.

  •exactly (adverb)
  • absolutely,
  • utterly,
  • precisely,
  • bang,
  • quite,
  • positively,
  • right,
  • truly,
  • faithfully,
  • just,
  • on the nose,
  • correctly,
  • altogether,
  • totally,
  • completely,
  • specifically,
  • sharp,
  • strictly,
  • wholly,
  • expressly,
  • definitely,
  • carefully,
  • truthfully,
  • literally,
  • square,
  • severely,
  • indeed,
  • scrupulously.
  •for sure (adverb)
  • sure thing,
  • for real,
  • no two ways about it,
  • really,
  • dead sure,
  • no doubt,
  • no question.
  •surely (adverb)
  • evidently,
  • indubitably,
  • assuredly,
  • conclusively,
  • clearly,
  • Doubtlessly,
  • plainly,
  • inevitably.

• n.

  •certainly (noun)
  • certainly.
  •for certain (noun)
  • sure,
  • sure as shooting,
  • surely.
  •without a doubt (noun)
  • easily.

• Other synonyms:

  •adj.
  • fated,
  • irresistible,
  • ordained,
  • self-explanatory,
  • unpreventable,
  • well-founded,
  • in the bag,
  • down pat,
  • inevitable,
  • sure-enough,
  • univocal,
  • unmistakable,
  • unquestionable,
  • Ineludible,
  • without recourse,
  • all locked up,
  • no ifs ands or buts,
  • open and shut,
  • sure enough.
  •adv
  • admittedly,
  • beyond doubt,
  • exactly,
  • faultlessly,
  • fixedly,
  • for sure,
  • methodically,
  • on the dot,
  • rigorously,
  • to be sure,
  • unequivocally,
  • unerringly,
  • unfailingly,
  • unmistakably,
  • unshakably,
  • Infallibly,
  • Veraciously,
  • irrefutably,
  • be sure,
  • come what may,
  • with certainty,
  • beyond shadow of doubt,
  • for a fact,
  • in deed,
  • in every respect,
  • no mistake,
  • on the nail.
  •adv.
  • explicitly,
  • inexorably,
  • manifestly,
  • rain or shine,
  • the ticket,
  • without fail,
  • nothing else but,
  • on the money.
  •n.
  • decidedly,
  • distinctly,
  • doubtless,
  • guaranteed,
  • undoubtedly,
  • unquestionably.

Antonyms for For certain:

• adj.

  • inevitable
    later, Escapable, unlikely, avoidable, preventable, distant, fortuitous, unsure, doubtful, uncertain.
  • unmistakable
    indistinct, vague, equivocal, ambiguous, secret, dubious, Mistakable, disputable, hidden, unclear, unknown, obscure, questionable.

• adv.

  • exactly
    incompletely, indefinite, doubtfully, inaccurately, dubiously, questionably, partially, inexactly.
  • surely
    vaguely, indefinitely.