Wordnet 3.0
NOUN (1)
1. 
 a native or resident of Missouri; 
The Collaborative International Dictionary of English v.0.48:
Missourian \Missourian\ prop. n.
   A resident of Missouri.
   [WordNet 1.5]
WordNet (r) 3.0 (2006):
Missourian
    n 1: a native or resident of Missouri