In·eff·a·ble

Too great, extreme, or beautiful to be expressed or described in words.

Refers to experiences, feelings, or concepts that are beyond verbal explanation.

"She felt an ineffable sense of peace during meditation."

Indescribable · Inexpressible · Unspeakable · Unutterable

From Latin ineffabilis, from in- (“not”) + effabilis (“able to be spoken”), from effari (“to speak out”).