the GNU version of the Collaborative International Dictionary of English
adj. Lowest.
The Century Dictionary and Cyclopedia
Lowest; undermost: as, the nethermost hell.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
adj. farthest down
Word Usage
"Styron writes, “Incomplete mourning has validity… and it is also true that in the nethermost depths of suicidal behavior one is still subconsciously dealing with immense loss while trying to surmount all the effects of its devastation.”"