I would recommend that you use "most swiftly" since swiftliest could sound a bit awkward.
more swiftly, most swiftly
There are: Comparative-more swiftly and superlative-most swiftly. Hope it helps you!
more swiftly, most swiftly
The superlative form of genuine is more genuine.
No, the superlative form is "gentlest."
Comparative: uglier Superlative: ugliest
Smoothest is the superlative form of the word smooth. The comparative form is smoother.
the comparative and superlative forms of the word near are nearer(in comparative form) and nearest(in superlative form).
If splendidest was a word, it would be a superlative. The comparative form of splendid is more splendid, the superlative form is most splendid.
The superlative for the word generous is most generous.
What's the superlative of shine
Commonest is the superlative of common.