The Collaborative International Dictionary of English v.0.48:
Anabaptist \An`a*bap"tist\, n. [LL. anabaptista, fr. Gr. as if
'anabaptisth`s: cf. F. anabaptiste.]
A name sometimes applied to a member of any sect holding that
rebaptism is necessary for those baptized in infancy.
Note: In church history, the name Anabaptists usually
designates a sect of fanatics who greatly disturbed the
peace of Germany, the Netherlands, etc., in the
Reformation period. In more modern times the name has
been applied to those who do not regard infant baptism
as real and valid baptism.
[1913 Webster] Anabaptistic