* Descent: This is the most direct opposite, meaning to move downwards.
* Decline: This implies a downward trend or a decrease in something.
* Fall: This suggests a sudden downward movement.
* Drop: This also suggests a sudden downward movement, often used for a decrease in value or level.
* Sinking: This implies a slow and gradual downward movement.
* Downturn: This refers to a downward trend in economic or social conditions.
The best antonym will depend on the specific meaning of "ascent" in your context.