Where does “অক্ষুণ্ণচিত্ত” come from?

অক্ষুণ্ণচিত্ত (Bengali) comes from Bengali চিত্ত, from Sanskrit चित्त, from Sanskrit चित्ति, from Proto-Indo-Iranian *čítˢtiš, from Proto-Indo-European *kʷéyt-ti-s ~ *kʷit-téy-s, from Proto-Indo-European kʷeyt- — to notice; to read.

অক্ষুণ্ণচিত্ত (Bengali): having no regret in mind, unperturbed