The word “unfathomable” means something that is impossible to understand or comprehend fully. It describes something that is extremely deep, mysterious, or beyond human comprehension.

Interesting fact: The word “unfathomable” originated from the Old English word “fæðm,” which means “to embrace or encircle with one’s arms.” Over time, it evolved to mean “to measure the depth of water by extending one’s arms.” Eventually, it took on the figurative meaning of something that is immeasurable or incomprehensible.