Undoing
来自Big Physics
Old English undōn (see un-2, do1).
wiktionary
From Middle English undoinge, undoynge, ondoynge; equivalent to undo + -ing.
From Middle English undoynge, undoand, from Old English undōnde(“undoing”), from Proto-Germanic *andadōndz, present participle of *andadōną(“to undo”). Cognate with Dutch ontdoend(“undoing”).
