mysterium tremendum

Mysterium tremendum is a Latin phrase meaning "fearful mystery" or "awe-inspiring mystery," used in religious and philosophical contexts to describe the overwhelming, terrifying aspect of encountering the divine or sacred.

The term was popularized by theologian Rudolf Otto to capture the experience of something wholly other—a presence that inspires dread, fascination, and a sense of one's own smallness simultaneously: Standing in the cathedral, she felt the mysterium tremendum of the space.

The phrase often pairs with mysterium fascinans (the attractive, compelling aspect of the holy) to describe the full range of religious experience.