unimaginable

Meanings

1. 1
   adj

   Unable to be imagined; inconceivable or mind-boggling; beyond belief.

   But at the microlevel it consists of an unimaginable number of atoms connected by springy chemical bonds, all jiggling around at a rate that even our fastest supercomputer might envy.

2. 2
   adj

   totally unlikely

Etymology

From un- + imagine + -able.