Manava Dharmashastra 3.157

3.157

vigarhito ninditaḥ ācāraḥ karmānuṣṭhānameṣāmiti | kāṇādayaḥ pūrvadoṣaliṅgena | stenādayo'nubhūyamānadoṣāḥ pratyakṣādinā | ubhayatra daive pitrye ca | varjayet pariharet | apāṅkteyāḥ, paṅktiṃ nārhanti | bhavārthe ḍhakarvtavyaḥ | anarhatvameva paṅktāvabhavanena pratīyate | anyairbrāhmaṇaiḥ saha bhojanaṃ nārhanti | ata eva 'paṅktidūṣakā' ucyante | taiḥ sahopaviṣṭā anye'pi dūṣitā bhavanti |

The learned Brāhmaṇa should avoid at both (rites) these l owest of twice-born men, who are of reprehensible conduct and who are unworthy of company.—(167)

Medhātithi’s commentary (manubhāṣya):
These men, whose ‘conduct’—line of action—is ‘reprehensible.’ The ‘blind’ and the rest having their previous misconduct indicated by these disabilities; while the ‘thief,’ etc., have their misconduct actually perceptible in the present.

‘At both’— rites for gods and pitṛs.

‘Should avoid’— should exclude.

‘Unworthy of company’—i.e., they do not deserve company. The ‘ḍhak’ affix denoting presence. Absence from company indicates unworthiness. That is, he does not deserve to eat in the company of other Brāhmaṇas. It is for this reason that such persons have been called ‘defilers of company;’ the meaning being that those who sit at dinner with them become defiled.—(167)