unfathomable

UK: ʌnˈfæðəməbl̩ | US: ʌnˈfæðəməbl̩

Definition

  1. adj. impossible to understand or measure; incomprehensible

  2. adj. (archaic) too deep to be measured

Structure
un <not>fathom <measure depth>able <capable of>
Etymology

The word "unfathomable" combines three morphemes:

  1. "un-" (Old English "un-"), a prefix meaning "not," negates the root.
  2. "fathom" (Old English "fæðm"), originally referring to the span of outstretched arms (a unit for measuring depth at sea), later metaphorically extended to mean "understanding."
  3. "-able" (Latin "-abilis"), a suffix indicating capability.
    The term evolved from literal ("too deep to measure") to figurative ("impossible to comprehend"), reflecting the transition of "fathom" from a physical to an abstract concept.
Examples

  1. The ocean's depths remain unfathomable to most explorers.

  2. Her grief was unfathomable after the sudden loss.

  3. The scientist faced an unfathomable problem with no clear solution.

  4. His motives were unfathomable, leaving everyone confused.

  5. The universe's vastness is truly unfathomable to the human mind.