Wordnet 3.0
NOUN (1)
1. 
 someone who claims to speak the truth; 
- Example: "a bold asserter"- Example: "a declarer of his intentions"- Example: "affirmers of traditional doctrine"- Example: "an asseverator of strong convictions"- Example: "an avower of his own great intelligence"[syn: asserter, declarer, affirmer, asseverator, avower]
WordNet (r) 3.0 (2006):
asseverator
    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]