What does Adam Smith mean by equality of condition?
The term "equality of condition" can also be thought of as "equality of outcome."

In this context, it refers to the idea that people in a society/state have approximately the same overall quality of life, regardless of opportunity, socioeconomic circumstances, prejudicial treatment, advantages/disadvantages, etc.

This is an oversimplification but, to put it another way, you could think of equality of opportunity (in regards to material wealth, access to luxuries, health and quality of life, etc.) as "equalizing how people start" and equality of condition as "equalizing how people finish."