Vishnupurana 3.18.103

3.18.103

ete pāṣaṇḍinaḥ pāpā na hy etān ālaped budhaḥ
puṇyaṃ naśyati saṃbhāṣād eteṣāṃ taddinodbhavam //

These, Maitreya, are the persons called naked, the meaning of which term you desired to have explained. Their very looks vitiate the performance of an ancestral oblation; speaking to then destroys religious merit for a whole day. These are the unrighteous heretics to whom a man must not give shelter, and speaking to whom effaces whatever merit he may that day have obtained. Men, indeed, fall into hell as the consequence of only conversing with those who unprofitably assume the twisted hair, and shaven crown; with those who feed without offering food to gods, spirits, and guests; and those who are excluded from the presentation of cakes, and libations of water, to the manes.