ˈfathəmlə̇s adjective
Etymology: fathom (II) + -less
: incapable of being fathomed : immeasurable
the fathomless depths of the ocean
a man of wealth and fathomless energy — Bruce Catton
: incomprehensible
a philosophy complex and, to the ordinary thinker, quite fathomless
• fath·om·less·ly adverb
• fath·om·less·ness noun -es