A verb for “undo” appearing in notes from around 1959 as a combination of nan- “back (again)” and car- “do” (PE17/166).
Neo-Quenya: Helge Fauskanger also used this verb to mean “destroy” in his NQNT (NQNT), but I prefer ᴺQ. fehta- this meaning; see that entry for discussion.
#nancar- vb. "undo" (destroy). Cited in the form nancari- ("k"), apparently including the connecting vowel of the aorist (PE17:166)