having great spatial extension or penetration; downward ("a deep well"; "a deep dive"; "deep water"; "a deep casserole"); or inward from an outer surface ("a deep gash"; "deep massage"; "deep pressure receptors in muscles"); or backward ("deep shelves"; "
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profound
showing intellectual penetration or emotional depths; from the depths of your being; "the differences are profound"; "a profound insight"; "a profound book"; "a profound mind"; "profound contempt"; "profound regret"
1
deep
strong; intense; "deep purple"; "a rich red"
1
unfathomable
of meaning; not capable of being penetrated; "a philosophy complex and, to the ordinary thinker, quite fathomless"; "unfathomable theories"
1
mysterious
having an import not apparent to the senses nor obvious to the intelligence; beyond ordinary understanding; "mysterious symbols"; "the mystical style of Blake"; "occult lore"; "the secret learning of the ancients"
1
unfathomable
of depth; not capable of being sounded or measured
1
countless
too numerous to be counted; "incalculable riches"; "countless hours"; "an infinite number of reasons"; "innumerable difficulties"; "the multitudinous seas"; "myriad stars"; "untold thousands"
1
immeasurable
impossible to measure; "unmeasurable reaches of outer space"