certainliest

Without doubt many acute, malign, and confuſed ſickneſſes, would be beſt, eaſilieſt and certainlieſt cured by Plants of that Planet that are antipathetical to the Planet that is found to cauſe the Diſeaſe; […]

1664, William Drage, “William Drage D. P. His Monitory Proæmium to the Candid Readers”, in A Physical Nosonomy: or, A New and True Description of the Law of God (Called Nature) in the Body of Man: […], London: […] J. Dover, for the Author, page [39]

Next to the Act of Cogitation and Volition itſelf, and to the moſt certain Objects of Sence, there is nothing in all the World ſo Certain, that is, ſo Evident to the Intellect, as the Being of God: He being that to the Mind which the Sun is to the Eye, certainlieſt known, though little of him be known, and no Creature comprehend him.

1689, Richard Baxter, “What are the Certainties that must be known and held fast, and why?”, in A Treatise of Knowledge and Love Compared. […], London: […] Tho[mas] Parkhurst […], part I (Of Falsly Pretended Knowledge), page 39

Uſe always the float and quill, angle for him [the carp] ſometimes above, and ſometimes below mid-water, as the weather is, tho’ in mid-water he is the certainlieſt taken, eſpecially in a pond, but in rivers he is very ſhy: […]

1758, “Of Angling”, in T[homas] Fairfax, compiler, The Compleat Sportsman; or Country Gentleman’s Recreation. […], London: […] J. Cooke, […], page 152