PTS Pali-English dictionary - The Pali Text Society's Pali-English dictionary
Niṭṭhurin
Niṭṭhurin,(adj.) [Sk.niṣṭhura or niṣṭhūra,ni+thūra= thūla; cp.Prk.niṭṭhura] rough,hard,cruel,merciless Sn.952 (a°; this reading is mentioned as v.l.by Bdhgh at SnA 569,& the reading anuddharī given; vv.ll.SS anuṭṭhurī,BB anuṭṭharī,expld as anissukī.Nd1 440 however has aniṭṭhurī with expln of nitthuriya as under issā at Vbh.357).(Page 357)