Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
harmless [ˈhɑːmlɪs] adj (animal, person) безоби́дный*безоби́ден (joke, activity) неви́нный*неви́нен
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.