deep

adjective:extending far down from the surface; situated far below the top or surface
- The diver explored the deep canyon beneath the coral reef.
adjective:intense, profound, or serious in feeling, thought, or quality
- She felt a deep sense of gratitude after the ceremony.
adjective:having a low pitch or tone; sounding resonant and rich
- His deep voice filled the auditorium.
noun:the deep sea or ocean, especially its remote or mysterious parts
- Scientists are constantly discovering new species in the deep.
noun:a profound or extensive depth of intellectual or emotional content
- The novel explores the deep of human loneliness.