An Aticāra (partial transgression) of the vow of Upabhoga-paribhogaparimāṇa (seventh vow of the lay follower);
to consume grain of worthless quality (such as the pod of a leguminous plant which is not fully developed) due to which there is more killing of the Jīvas (living beings) but less satiation.
'tucchosahibhakkhaṇaya' tti tucchāḥ - asārā ausadhayaḥ aniṣpannamudgaphalīprabhṛtayaḥ tadbhakṣane hi mahatīvirādhanā svalpā ca tat- kāryā tṛptiḥ.
(UPā 1.38 Vṛ p. 16)