Synonyms of unfathomable

Adjective

1. unfathomable (vs. fathomable), unsoundable, deep

usage: of depth; not capable of being sounded or measured

2. abysmal, abyssal, unfathomable, deep (vs. shallow)

usage: resembling an abyss in depth; so deep as to be unmeasurable; "the abyssal depths of the ocean"

3. unfathomable, incomprehensible (vs. comprehensible), uncomprehensible

usage: impossible to come to understand