A kind of Prāyaścitta (expiation);
the Tapa (penance) like māsalaghu etc. undertaken as the performance of expiation; the Tapa during which ten kinds of activity such as talking, co-eating and the like are prohibited for the penancer; (parihāra means prohibition).
'parihāro' māsalaghukādistapoviśeṣaḥ.
(Ka 2.4 Vṛ)
esa tavaṃ paḍivajjati, na kiṃci ālavati mā ya ālavaha. attaṭṭhaciṃtagassā, vāghāto bhe na kāyavvo.
(VyaBhā 549)
See - Śuddha Tapa.