profound

adj. (-er, -est) 1 having or demanding great knowledge, study, or insight (profound treatise; profound doctrines). 2 intense, unqualified, thorough (a profound sleep; profound indifference). 3 deep (profound crevasses).  profoundly adv. Profoundness n. Profundity n. (pl. -ies). [latin profundus]

a. Descending far below the surface; opening or reaching to a great depth; deep.