Declension table of ?tastanvas

Neuter	Singular	Dual	Plural
Nominative	tastanvat	tastanuṣī	tastanvāṃsi
Vocative	tastanvat	tastanuṣī	tastanvāṃsi
Accusative	tastanvat	tastanuṣī	tastanvāṃsi
Instrumental	tastanuṣā	tastanvadbhyām	tastanvadbhiḥ
Dative	tastanuṣe	tastanvadbhyām	tastanvadbhyaḥ
Ablative	tastanuṣaḥ	tastanvadbhyām	tastanvadbhyaḥ
Genitive	tastanuṣaḥ	tastanuṣoḥ	tastanuṣām
Locative	tastanuṣi	tastanuṣoḥ	tastanvatsu

Compound tastanvat -

Adverb -tastanvat