The 'four falls'; four inverted views, which cause one to fall from the true path (viparyāsa-catuksa). They are: (1) the fall of permanence--taking the impermanent to be permanent; (2) Enjoyment--perceiving suffering as enjoyment; (3) Purity-- seeing the impure as pure; (4) Self--perceiving what is not a self to be a self. These can be found in the Vimalakīrti-nirdeśa-sūtra 維摩經, as well as the Abhidharmakośa-bhāsya 倶舎論.

viparyāsa-catuṣka, caturvidha-viparyāsa.

佛教漢梵大辭典, 平川彰 Buddhist Chinese-Sanskrit Dictionary, Akira Hirakawa

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