GNU Collaborative International Dictionary of English

Found one definition

1.       
   Ranter (răntẽr), n.
   1. A noisy talker; a raving declaimer.
   
   [1913 Webster]
   
   
   2. (Eccl. Hist.) (a) One of a religious sect which sprung up in 1645; -- called also Seekers. See Seeker. (b) One of the Primitive Methodists, who seceded from the Wesleyan Methodists on the ground of their deficiency in fervor and zeal; -- so called in contempt.
   
   [1913 Webster]