Vastly vs. Fastly: What's the Difference?
Vastly and Fastly Definitions
Very great in size, extent, or quantity.
In a secure or firm manner; securely
We tied the rope fastly this time; we didn't want it to get away again.
Very great in scope or import
A vast improvement.
An immense space.
Greatly, in a vast manner.
To a vast extent or degree; very greatly; immensely.
To an exceedingly great extent or degree;
He had vastly overestimated his resources
Was immensely more important to the project as a scientist than as an administrator