D defs.my
Entry 1 sense Webster, 1913

Theorist

/thē'-ẽr-ĭst/ · The·o·rist · IPA /ˈθiːəɹəst/
01 n. One who forms theories; one given to theory and speculation; a speculatist.
  1. 1.
    One who forms theories; one given to theory and speculation; a speculatist.
    “The greatest theoretists have given the preference to such a government as that which obtains in this kingdom.” Addison.