What do you think of prelest as a translation for this, Ven?
The wikipedia article focuses a lot on defining the term from a particularly Christian perspective, but what it generally means is a person ego-inflated belief about one’s progress in the holy life in a monastic setting. In a Christian setting, people who have prelest are often believed to vainly speak in tongues, claim to have visions of God, etc., and it, unrelated, but it sometimes becomes a point of polemical critique against movements like Pentecostalism and Charismaticism.
Aside concerning defining prelest and Christian monasticism
If it please you, an aside concerning the above.
At around 8:18 in this video, Father Archimandrite Zacharias, who was a disciple of Elder Sophrony, who was a disciple of Saint Silouan of the Autonomous Monastic State of the Holy Mountain (Mt. Athos), and who is a practitioner of hesychast meditation, will speak about the vainglory his spiritual father, Saint Silouan, struggled with on account of an initial breakthrough in spiritual attainment (which seems to be a brief illumination of the nous, or noetic faculty, which hesychast meditators seek to attain, believed to be a closeness to God, but that is my spin, not his language) at an unready stage of cultivation and his failure to maintain that state, resulting a depression of sorts and a period of struggling with internal prelest, which I think is the vainglory Father Zacharias is saying in English.
For instance, the demon that St. Silouan comes to fight with which appears before the icon of Christ need not be interpreted as a spirit from hell, but instead as an “internal demon” of vain-glory and this would not be a particularly off-the-wall reading. The injunction “keep your mind in hell” is very interesting here. Struggling with demons is a traditional element of the symptoms of prelest in Christianity, so that is a reason why the term might not be culturally appropriate. I don’t know if monks who lie about attainments are said to be hounded by spirits and Māra in Theravāda monastic literature as well.
Unrelated to the subject matter, but interesting miscellany: at 25:19 there is a discourse on the “heart” (which here is a translation of the Greek term nous, analogous to citta) and the purification of said heart, which I found very illuminating.
At 33:00, he speaks of a polarity between “things eternal” and “things of this world” which can easily be read as “unconditioned” and “things conditioned”.