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
Roughly. Hope this helps! :)
rapidly celeritously
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