1. 
[syn: asserter, declarer, affirmer, asseverator, avower]
The Collaborative International Dictionary of English v.0.48:
Asserter \As*sert"er\, n.
   One who asserts; one who avers pr maintains; an assertor.
   [1913 Webster]
         The inflexible asserter of the rights of the church.
                                                  --Milman.
   [1913 Webster]
WordNet (r) 3.0 (2006):
asserter
    n 1: someone who claims to speak the truth; "a bold asserter";
         "a declarer of his intentions"; "affirmers of traditional
         doctrine"; "an asseverator of strong convictions"; "an
         avower of his own great intelligence" [syn: asserter,
         declarer, affirmer, asseverator, avower]