unfathom

Etymology
From, possibly created by analogy with , , etc.

Verb

 * 1)  to come to comprehend; demystify.

Usage notes
Though attested for over 100 years, the word unfathom is absent from most dictionaries. It is considered by some to be an erroneous formation stemming from a lack of understanding that fathom itself already has the correct meaning, or a confusion with other un- words with similar meaning such as unravel, or erroneous transference of the prefix from unfathomable or unfathomed.