unfathomable

[uhn-fath-uh-muh-buhl]

adjective

1. not able to be fathomed, or completely understood; incomprehensible.

   heroism in the face of unfathomable conflict.

2. not able to be measured with a sounding line, or fathomed.

   unfathomable depths of the ocean.

unfathomable

/ ʌnˈfæðəməbəl /

adjective

1. incapable of being fathomed; immeasurable

2. incomprehensible

Other Word Forms

• unfathomableness noun
• unfathomably adverb

Word History and Origins

Origin of unfathomable¹

First recorded in 1610–20; un- ¹ ( def. ) + fathom ( def. ) + -able ( def. )

Example Sentences

They described the comments as "horrific" and "unfathomably heartless".

From BBC

In a statement posted on social media, Mastodon said they were in a "state of unfathomable sadness and grief".

From BBC

Played with a straight face, “Weapons” could ignite major, necessary conversations about the fear parents have of sending their children to school and the long-term ramifications of unfathomable violence.

From Salon

It started with a season that delivered the most unlikely - and previously unfathomable - Premier League title to King Power Stadium in 2016.

From BBC

Chancellor Kathaleen McCormick, the judge in the case, sided with Tornetta and rescinded the entire pay package, calling it an “unfathomable sum.”

From Los Angeles Times

Related Words

• baffling 
• impenetrable 
• incomprehensible 
• indecipherable 
• inexplicable 
• unknowable