Collins Russian Dictionary 2nd Edition © HarperCollins Publishers 2000, 1997:
imprudent [ɪmˈpruːdnt] adj неблагоразу́мный*неблагоразу́мен
it would be imprudent of you to insult him оскорби́ть его́ бу́дет неблагоразу́мием с Ва́шей стороны́
* is used to mark translations which have irregular inflections. The Russian-English side of the dictionary gives inflectional information.
Русский: