\Syn"cre*tist\, n. [Cf. F. syncr['e]tiste.]
One who attempts to unite principles or parties which are
irreconcilably at variance; specifically (Eccl. Hist.), an
adherent of George Calixtus and other Germans of the
seventeenth century, who sought to unite or reconcile the
Protestant sects with each other and with the Roman
Catholics, and thus occasioned a long and violent controversy
in the Lutheran church.