A sub-category of Kaṣāya Kusīla Nirgrantha (3) That ascetic (Muni), who, by indulging in anger, pride etc. even when involved in the process of knowledge, vitiates knowledge.
ṇāṇaṃdaṃsaṇaliṃge jo juṃjai kohamāṇamāihim.
so nāṇāikusīlo kasāyao hoi vinneo..
cārittaṃmi ktisilo, kasāyao jo payacchaī sāvaṃ.
maṇasā kohāīe, nisevayaṃ hoi ahasuhumo..
aliavāvi kasāehiṃ nāṇāīṇaṃ virāhao jo u.
so nāṇāikusīlo ṇeo vakkhāṇabheeṇaṃ..
(Bhaga 25.283 Vṛ)