Nirgrantha，又作尼虔，尼乾，尼健。六大外道之一。尼犍具曰尼犍陀。譯曰離繫，不繫，無結。離三界繫縛之義也。是為外道出家之總名。但此外道，特修裸形塗灰等離繫之苦行，故取總名為別名。自佛法毀之，名曰無慚。以彼母之名名為若提Jñātī，譯曰親友。彼為其子，故曰尼乾陀若提子Nirgranthajñātiputra，又師之門徒，曰尼乾陀弗咀羅Nirgranthaputra，尼乾子，尼乾陀子。弗咀羅譯為子，指稱門徒。注維摩經三：「肇曰：尼犍陀其出家總名也。如佛法出家名沙門，若提母名也。其人謂罪福苦樂本有定因，要當必受，非行道所能斷也。」法華文句記九曰：「在家事梵名梵志，出家外道通名尼乾。」唯識述記一本曰：「尼虔子，今言尼犍陀弗咀羅，翻為離繫子。苦行修勝因名為離繫，露形少羞恥，亦名無慚。本師稱離繫，是彼門徒，名之為子。」同一末曰：「以其露形，佛法毀之曰無慚，即無慚羞也。」慧琳音義二十六曰：「尼乾陀此云無繼，是外道總名也。若提云親友，是母名。」玄應音義六曰：「尼乾或作尼乾陀，應言泥健連他，譯云不繫也。」同十曰：「其外道，拔髮露形，無所貯蓄，以手乞食，隨得即噉也。」俱舍光記十五曰：「離擊，梵云尼乾陀。彼謂內離煩惱擊縛，外離衣服擊縛，即露形外道也。」
nirgrantha, 尼健; 尼乾 (尼乾陀); 尼虔, freed from all ties, a naked mendicant, tr. by 離繋, 不繋, 無結 devotees who are free from all ties, wander naked, and cover themselves with ashes. Mahāvīra, one of this sect, called 若提 Jñāti after his family, and also 尼乾陀若提子 Nirgrantha-jñātiputra, was an opponent of Śākyamuni. His doctrines were determinist, everything being fated, and no religious practices could change one's lot.