Mammoth Uncensored Word List:
44 - 14 letter words starting with do

doctrinairisms doctrinalities documentalists documentarians documentarised documentarises documentarists documentarized documentarizes documentations dodecahedranes dodecaphonisms dodecaphonists dodecasyllabic dodecasyllable dogmaticalness dogmatisations dogmatizations dolichocephals dolichocephaly dollarisations dollarizations dollarocracies dolomitisation dolomitization dolorousnesses domestications domesticworker domiciliations doparesponsive dorsalizations dorsiventrally dorsolaterally dorsoventrally dosimetricians doublechecking doublecrossing doublehandedly doublespeakers doublestranded doubtfulnesses downregulating downregulation downwardnesses