Which term refers to matters that are related to the church or its clergy?

The term that refers to matters related to the church or its clergy is "ecclesiastic." This word is derived from the Greek "ekklēsia," meaning "assembly" or "church." It specifically pertains to the organizational aspects and functions of the church, including its hierarchy, governance, and clerical roles. Ecclesiastic matters may involve church policies, the administration of sacraments, and the duties of clergy members.

In contrast, "liturgical" pertains to the formal rituals and worship practices of a religious tradition but does not necessarily encompass the broader organizational elements associated with ecclesiastical matters. "Secular" refers to non-religious affairs and activities that do not involve the church or its clergy, while "religious" is a general term that can apply to various aspects of belief systems and practices, but lacks the specific connection to the church's governance and its clergy that "ecclesiastic" conveys.