Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
untoward [ʌntəˈwɔːd] adj (events) скве́рный*скве́рен (effects) отрица́тельный*отрица́телен
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.