Sindarin 

dangar

verb. to undo

_ v. _to undo. Q. nankari-. >> dan-

Sindarin [(PE17 Sindarin Corpus) PE17:166] < NDAN + ?. Group: Parma Eldalamberon 17 Sindarin Corpus. Published by

dangar-

verb. to undo

A verb for “undo” appearing in notes from around 1959 as a combination of dan “back again” and car- “do” (PE17/166).

Sindarin [PE17/166] Group: Eldamo. Published by

Quenya 

nancar-

verb. to undo, to undo, *destroy

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.