Asādhāraṇam — The Uniquely Divine, The Restricted
Asādhāraṇam ('not belonging to all, not common, particular') is used in two primary senses in Śrī Vaiṣṇava theological discourse.
In theological analysis of Bhagavān's nature: the asādhāraṇa-viśeṣaṇas (uniquely differentiating attributes) of Śrīman Nārāyaṇa are those qualities that set Him apart from all other beings and categories — including the liberated souls (muktas), the eternally liberated (nitya-sūris), and other deities. These include: nirupādhika-svasāmarthya (power without support or dependence on anything), saguṇa-brahmatvam (being simultaneously beyond all and personally involved with all), sovereignty over both vibhūtis (both realms of manifestation), śrī-sāhitya (inseparable association with Śrī Mahālakṣmī who recommends all souls). These attributes are asādhāraṇam — uniquely and exclusively Bhagavān's.
In classification of upāyas (paths to liberation): bhakti-yoga is asādhāraṇam in the sense of being restricted — it requires the practitioner to be a dvija (twice-born, i.e., from Brāhmaṇa, Kṣatriya, or Vaiśya varṇa), to have undergone the Vedic upanayana rite, to have sufficient intellectual and mental purity for sustained meditation, and to dedicate many lifetimes to the practice. These prerequisites make bhakti-yoga genuinely inaccessible to most souls in their current condition — making prapatti (which is sādhāraṇam) the more universally applicable path.
The theological use of asādhāraṇam for Bhagavān's attributes supports the Viśiṣṭādvaita refutation of both Advaita (which would reduce Bhagavān to an undifferentiated Absolute without asādhāraṇa qualities) and Dvaita (which attributes certain asādhāraṇa qualities to individual jīvas at their highest state). For Rāmānujāchārya, the asādhāraṇa qualities remain eternally and uniquely Bhagavān's — even the liberated soul (mukta) in Paramapadham enjoys Bhagavān's presence and attributes through reflection, not identity.
Understanding asādhāraṇam helps the devotee maintain proper parathva (understanding of Bhagavān's supreme uniqueness) even while cultivating the most intimate devotion — the two are not in tension for Viśiṣṭādvaita.