Wiktionary
flashingly
adv. With a flashing appearance.
Usage examples of "flashingly".
And, suddenly, he foresaw flashingly that even they would be able to do nothing.
But the night outside, with its flashingly bright sun off to one side and everywhere else starry darkness, was an unchanging environment.
As he reached this chamber, he was flashingly aware of some small squat bulk on the floor ahead of him.