Esoteric and Unplumbed

Esoteric adjective - Difficult for one of ordinary knowledge or intelligence to understand.

Unplumbed and esoteric are semantically related. In some cases you can use "Unplumbed" instead an adjective "Esoteric".

Unplumbed adjective - Situated at or extending to great depth; too deep to have been sounded or plumbed.

Esoteric and unplumbed are semantically related. Sometimes you can use "Esoteric" instead an adjective "Unplumbed".