vast + -ly
vastly (comparative more vastly, superlative most vastly)
- Greatly, in a vast manner.
1913, Robert Barr, chapter 1, in Lord Stranleigh Abroad:
“I have visited my quarters, and find them very comfortable. […] Steerage is like everything else maritime […] vastly improved since Robert Louis Stevenson took his trip third class to New York.”
greatly, in a vast manner