Wordnet 3.0
NOUN (1)
1. 
 a trader who exchanges goods and not money; 
The Collaborative International Dictionary of English v.0.48:
Barterer \Bar"ter*er\, n.
   One who barters.
   [1913 Webster]
WordNet (r) 3.0 (2006):
barterer
    n 1: a trader who exchanges goods and not money