simple-minded russian

• простоду́шный

  open-hearted, simple-hearted, simple-minded, artless, unsophisticated

• глу́пенький

  silly, naive, simple-minded, a bit foolish

• прихло́пнутый

  swatted, crushed

  a bit crazy, simple-minded, foolish, daft

• простоду́шие

  open-heartedness, simple-heartedness, simple-mindedness, artlessness, ingenuousness