Flumpf

"The wind caught the reserve canopy, billowed it out. For a hideous instant, he thought the reserve lines would wrap around the mains and he’d repeat Komarov’s messy death. Then—Flumpf! The reserve canopy snapped open, seemed to yank him skyward."

"It was true enough that Thomasina was on her terrace and looking into his apartment, although spying was a harsh word. “I’ll fix that,” Steve said. He moved over in full view of Thomasina and let the Venetian blind down with a flumpf."

"He sniffs himself suspiciously and then flumpfs into the couch, still wearing his peel."