Tough to penetrate or understand; profound; -- opposed to shallow or superficial; intricate; mysterious; not clear; obscure; as, a deep subject or plot deep - owning terrific spatial extension or penetration downward or inward from an outer area or backward or laterally or outward from the center; sometimes used together; https://bulk-whatsapp-marketing-s91245.develop-blog.com/43001024/top-guidelines-of-foundation-pile-testing-bd