Yes.
more swiftly, most swiftly
The word swiftly is an adverb. It means in a swift manner.
The river current moves more swiftly in the narrow channel. The army moved swiftly to prevent looting after the earthquake.
quickly or rapidly.
Speedily
rapidly celeritously
Roughly. Hope this helps! :)
Swiftly means to do something quickly and with great speed or promptness.
I would recommend that you use "most swiftly" since swiftliest could sound a bit awkward.
The word 'swiftly' is an adverb, a word that modifies a verb. Some examples:We ran swiftly to the bus stop, just in time to wave good-bye as the bus sped away.The kids swiftly made their bed because they could smell bacon and pancakes.
Fast
flew