Valmiki Ramayana Aranya Kanda Sarga 53 Shloka 8
Original Shlokaकथयिष्यन्ति लोकेषु पुरुषाः कर्म कुत्सितम्। सुनृशंसमधर्मिष्ठं तव शौण्डीर्यमानिनः।।3.53.8।।
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शौण्डीर्यमानिनः considering yourself to be brave, तव yourself, सुनृशंसम् this very cruel act, अधर्मिष्ठम् unrighteous, कुत्सितम् despised by others, कर्म action, लोकेषु in the worlds, पुरुषाः people, कथयिष्यन्ति will talk about.
You consider yourself to be brave after committing such a cruel, despicable and unrighteous act for which people of the world will condemn you.