The Collaborative International Dictionary of English v.0.48:

Traditionalist \Tra*di"tion*al*ist\, n.
   An advocate of, or believer in, traditionalism; a
   traditionist.
   [1913 Webster]

WordNet (r) 3.0 (2006):

traditionalist
    adj 1: stubbornly conservative and narrow-minded [syn:
           hidebound, traditionalist]
    n 1: one who adheres to traditional views [syn:
         traditionalist, diehard]