1. superlative form of deep; extending farthest down from the surface or top
2. most intense or extreme in degree
3. most thorough or complete in understanding or knowledge

Examples

• The Mariana Trench is the deepest part of the ocean.
• She fell into the deepest sleep after the long journey.
• His deepest fear was being alone.
• The philosopher had the deepest understanding of human nature.
• They dug the deepest hole they could manage.
• Her deepest regret was not calling her grandmother more often.
• The deepest snow was found in the mountain valleys.