This adjective first appeared as ᴱQ. pirūkea or ᴱQ. pirukenda “pirouetting” in the Qenya Lexicon of the 1910s under the early root ᴱ√PIRI (QL/74). It reappeared as pirukendea in the version of the Nieninqe prayer from around 1930, in the phrase ᴱQ. norolinde pirukendea “tripping lightly, whirling lightly” (MC/215). In the version of Nieninquë from the 1950s, Tolkien gave a different explanation for its meaning as a combination of piru “toes (dual)” and an adjective form of cendë “point”, hence meaning “on the point of her toes” (PE16/96).
Neo-Quenya: For purposes of Neo-Quenya, I would assume this was a poetic word, not in common use.
pirucendëa adj. "on the points of her toes" (PE16:96); see pirë, cendë. In earlier "Qenya", the word had a wholly different meaning: adj. "whirling lightly" (MC:215). Compare pirucenda ("k") "pirouetting" in QL:74.