In this same short-story I found VN used the word "leggy",
which also came up in the list in relation to Pnin's "leggy thing". Here it
comes, on page 335: "During those first warm days
everything seemed beautiful and touching: the leggy little
girls playing hopscotch on the sidewalk, the old men on the benches,
the green confettti...every time the air stretched its invisible
limbs."
The corresponding phrase in Sovershenstvo, the Russian original of
"Perfection", is golenastye devochki. On the second thought, I might have
translated "leggy thing" in Pnin as golenastyi, or even golenasten'kiy, predmet.
It all depends on the context at which I don't have the time to look closer. You
can see in my English how deeply engrossed in my article I am.
Alexey