Difficult or impossible to understand; incomprehensible

unfathomable theories.

of depth; not capable of being sounded or measured[ant: fathomable ]

resembling an abyss in depth; so deep as to be unmeasurable; "the abyssal depths of the ocean"[syn: abysmal ]

impossible to come to understand

adjective

comprehensible , explainable , explicable , fathomable , believable

adjective

abysmal , boundless , deep , eternal , immeasurable , infinite , soundless , unending , unmeasured , unplumbed , abstruse , baffling , clear as mud , enigmatic , esoteric , heavy , impenetrable , incognizable , incomprehensible , indecipherable , inexplicable , obscure , profound , too deep , uncomprehensible , ungraspable , unintelligible , unknowable , inscrutable , abyssmal , bottomless , complex , mysterious , vast