This is the 736th most frequent French word.
vaste
Extensive or spacious.
Here, "vaste" is used to convey that the discussion is wide-ranging or comprehensive.
Nous avons eu une discussion vaste sur le sujet.
We had a broad discussion on the topic.
The word "vaste" describes the size of the yard, implying that it is extensive or spacious.
Cette maison a une cour très vaste.
This house has a very large yard.
In this case, "vaste" denotes the breadth or depth of knowledge or experience the person has in the specific area.