Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
undoing [ʌnˈduːɪŋ] n (downfall) ги́бель f
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
undo [ʌnˈduː]
irreg
like do
vt (unfasten, laces, strings) развя́зывать (развяза́ть*perf)
(:buttons) расстёгивать (расстегну́ть perf)
(spoil) губи́ть*(погуби́ть*perf)
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.