rig·or·ist I. \-gərə̇st\noun (-s) Etymology: French rigoriste, from Latin rigor + French -iste -ist 1.: one who is strict in adherence to or enforcement of rules, standards, laws, or principles 2.: one who professes rigorism II. adjective orrig·or·is·tic\|rigə|ristik\ 1.: rigid in principles or actions : strict 2.: of or relating to the doctrine of rigorism