ArnoldistCh.Hist.|ˈɑːnəldɪst| Also Arnaldist. A follower of Arnold (or Arnaldus) of Brescia, a reformer of the 12th century. 1669Penn No Cross, etc. xx. §18 They [the Waldenses] had many other names, as Arnoldists, Esperonists.1882Schaff Herzog's Encycl.Rel.Knowl. I. 150.