icchantika ［一闡提］ (;  issendai): A person of incorrigible disbelief. Icchantika means one who is filled with desires or cravings. Originally icchantika meant a hedonist or one who cherishes only secular values. In Buddhism, the term came to mean those who neither believe in Buddhism nor aspire for enlightenment and therefore have no prospect of attaining Buddhahood. Many sutras say that icchantikas are inherently and forever incapable of reaching enlightenment, but some sutras hold that even icchantikas can become Buddhas. This discrepancy concerning the potential of such people to attain enlightenment became a source of considerable debate among Buddhist schools over the centuries.
  The term icchantika also refers to one who slanders the correct teaching of the Buddha and does not repent and rectify the error. The Nirvana Sutra translated by Dharmaraksha says: “Chunda spoke once more, asking, ‘What is the meaning of the term icchantika?’ The Buddha said: ‘Chunda, suppose there should be monks or nuns, laymen or laywomen who speak careless and evil words and slander the correct teaching, and that they should go on committing these grave acts without ever showing any inclination to reform or any sign of repentance in their hearts. Persons of this kind I would say are following the path of the icchantika. Again there may be those who commit the four grave offenses or are guilty of the five cardinal sins, and who, though aware that they are guilty of serious faults, from the beginning have no trace of fear or contrition in their hearts or, if they do, give no outward sign of it. When it comes to the correct teaching, they show no inclination to protect, treasure, and establish it over the ages, but rather speak of it with malice and contempt, their words replete with error. Persons of this kind too I would say are following the path of the icchantika.’” It also says, “Good man, there are icchantikas, or persons of incorrigible disbelief. They pretend to be arhats, living in deserted places and speaking slanderously of the correct and equal sutras of the great vehicle. When ordinary people see them, they all suppose that they are true arhats and speak of them as great bodhisattvas.”
  In this sense, icchantika refers not simply to those who have no exposure to or interest in Buddhism, but to those who feign Buddhist faith and understanding for self-serving ends. The Nirvana Sutra, however, says, “All living beings alike possess the Buddha nature,” thus revealing that icchantikas can also attain Buddhahood. The Lotus Sutra says, “At the start I [the Buddha] took a vow, hoping to make all persons equal to me, without any distinction between us, and what I long ago hoped for has now been fulfilled.” In this sutra, Devadatta, who symbolizes the icchantika, is assured of becoming a Buddha in the future.