(a.) Pertaining to, or resembling, an abyss; bottomless; unending; profound.

Atlantean Brobdingnagian Cyclopean Gargantuan Herculean Homeric abyssal appalling astronomic awful bottomless cavernous colossal deep as hell dreadful elephantine enormous epic fathomless gaping giant giantlike gigantic heroic huge illimitable immense infinite jumbo mammoth mighty monster monstrous monumental mountainous plumbless plunging prodigious profound soundless stupendous terrible titanic towering tremendous unfathomable unfathomed unsounded vast without bottom yawning