Prob"a*bil*ist, n. [Cf. F. probabilists.]
1.
One who maintains that certainty is impossible, and that probability alone is to govern our faith and actions.
2. Casuistry
One who maintains that a man may do that which has a probability of being right, or which is inculcated by teachers of authority, although other opinions may seem to him still more probable.
© Webster 1913.