what's more; moreover; at that
Adds an additional, often emphatic, point to a preceding statement. Can introduce a positive or negative addition.
He is smart. What's more, he is a hard worker.
Used to introduce a contrasting or unexpected statement after a preceding one. Similar to それなのに or それでも.
It started raining. And at that, it's a heavy downpour.
He is very busy. And yet, he goes to the gym every day.