Definition of originalist:
(n) :
One who aims to discover how the writers of a document intended it to be interpreted, and to interpret it in that way.
(n) :
(US politics) Specifically, one who aims to discover how the writers of the Constitution of the United States intended it to be interpreted, and to interpret it in that way.
(n) :
(theology) Specifically, one who aims to discover how the writers of the Jewish and Christian scriptures intended them to be interpreted, and to interpret them in that way.
(n) :
One who has, or tends to have, original ideas.