Valmiki Ramayana Aranya Kanda Sarga 33 Shloka 22
Original Shlokaत्वं तु रावण दुर्बुद्धिर्गुणैरेतैर्विवर्जितः। यस्य तेऽविदितश्चारै रक्षसां सुमहान्वधः।।3.33.22।।
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रावण Ravana, दुर्बुद्धि: evilminded, त्वं तु you are, एतैः by these, गुणैः qualities, विवर्जितः you are devoid of, यस्य whose, ते your, रक्षसाम् of demons, सुमहान् very great, वधः destruction, चारैः by spies, अविदितः was not known.
O Ravana you are evilminded. You are devoid of all these good qualities. Your spies could not know that there had been a great massacre of your fellowdemons.