doubt + -est <span class="searchmatch">doubtest</span> (archaic) second-person singular simple present indicative of doubt...
other whyche throughe the mortifyenge of the fleſhe: ledeth to lyfe, why <span class="searchmatch">doubteſt</span> thou in thy ſelf: There is no thyrde way. 1579, Immeritô [pseudonym; Edmund...
Gubbin, and I[ohn] Porter, →OCLC, page 245: [H]eerein thou vvauereſt and <span class="searchmatch">doubteſt</span>. a. 1812 (date written), Richard Cumberland, “The Sybil, or The Elder Brutus...