deciser
/dɪˈsʌɪzə/noun
A person who resolves or settles matters or controversies. In later use (Judaism ): a rabbi who decides matters in Jewish religious law.
Origin
Mid 16th century; earliest use found in John Foxe (?1517–1587), martyrologist. From classical Latin dēcīs-, past participial stem of dēcīdere decide + -er.