Question

unfathomable means :
impossible to come to understand
highly offensive; arousing aversion or disgust
appropriate for ordinary or routine occasions
able to be arranged by compromise

Explanation:

The word "unfathomable" is derived from the verb "fathom," which means to understand or comprehend. The prefix "un - " indicates negation. So, "unfathomable" means not able to be fathomed or understood.

Answer:

impossible to come to understand