Declension table of ?kaṣṭavat

Masculine	Singular	Dual	Plural
Nominative	kaṣṭavān	kaṣṭavantau	kaṣṭavantaḥ
Vocative	kaṣṭavan	kaṣṭavantau	kaṣṭavantaḥ
Accusative	kaṣṭavantam	kaṣṭavantau	kaṣṭavataḥ
Instrumental	kaṣṭavatā	kaṣṭavadbhyām	kaṣṭavadbhiḥ
Dative	kaṣṭavate	kaṣṭavadbhyām	kaṣṭavadbhyaḥ
Ablative	kaṣṭavataḥ	kaṣṭavadbhyām	kaṣṭavadbhyaḥ
Genitive	kaṣṭavataḥ	kaṣṭavatoḥ	kaṣṭavatām
Locative	kaṣṭavati	kaṣṭavatoḥ	kaṣṭavatsu

Compound kaṣṭavat -

Adverb -kaṣṭavantam