Declension table of ?pastyāvat

Masculine	Singular	Dual	Plural
Nominative	pastyāvān	pastyāvantau	pastyāvantaḥ
Vocative	pastyāvan	pastyāvantau	pastyāvantaḥ
Accusative	pastyāvantam	pastyāvantau	pastyāvataḥ
Instrumental	pastyāvatā	pastyāvadbhyām	pastyāvadbhiḥ
Dative	pastyāvate	pastyāvadbhyām	pastyāvadbhyaḥ
Ablative	pastyāvataḥ	pastyāvadbhyām	pastyāvadbhyaḥ
Genitive	pastyāvataḥ	pastyāvatoḥ	pastyāvatām
Locative	pastyāvati	pastyāvatoḥ	pastyāvatsu

Compound pastyāvat -

Adverb -pastyāvantam