Parihāna-dhamma: 'liable to decline'.;Now, someone reaches the attainments absorptions: Jhanas of the fine-material or immaterial sphere see: avacara But he does not reach them according to his wish, and not without trouble and exertion; and not according to his wish with regard to place, object and duration, does he enter them, or rise therefrom. Therefore it is well possible that such a monk, through negligence, may lose these attainments. Such a person is said to be liable to decline; Pug. 5.
Maha Thera Nyanatiloka. Manual of Buddhist Terms and Doctrines, Buddhist Publication Society, first edition 1952.