The Collaborative International Dictionary of English v.0.48:

Dissentient \Dis*sen"tient\, a. [L. dissentiens, p. pr. of
   dissentire. See Dissent, v. i.]
   Disagreeing; declaring dissent; dissenting. -- n. One who
   dissents. --Macaulay.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dissentient
    adj 1: (of Catholics) refusing to attend services of the Church
           of England [syn: dissentient, recusant]
    2: disagreeing, especially with a majority [syn: dissentient,
       dissenting(a), dissident]