The Authority of Exemplary Conduct
Siṣṭācāram (Sanskrit: siṣṭa = the refined/virtuous + ācāra = conduct) refers to the practices and behaviors of the siṣṭas — the exemplary, learned, and virtuous members of the community whose lives embody the tradition. Their conduct (ācāra) is treated as a valid source of dharmic authority alongside scripture.
Three Sources of Authority
Dharmaśāstra tradition recognizes three sources: (1) Vedic scripture, (2) Smṛti texts, and (3) the conduct of good men (siṣṭācāra). Where scripture is silent or ambiguous, siṣṭācāram fills the gap — 'how did the great Ācāryas conduct themselves?' becomes the normative question.
In Śrī Vaiṣṇava Life
The particular practices of respected senior Śrī Vaiṣṇavas — how they conduct daily worship, how they speak, how they treat guests, what foods they accept — constitute the living siṣṭācāram of the community. This is why the tradition greatly values learning by living in close proximity to a realized Ācārya: doctrine is transmitted through both word and example.