Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
nonsense [ˈnɔnsəns] n (rubbish) ерунда́, чепуха́
it is nonsense to say that ... говори́ть (сказа́ть*perf), что ... -- про́сто глу́пость
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
Русский: