Declension table of ?grastatva

Neuter	Singular	Dual	Plural
Nominative	grastatvam	grastatve	grastatvāni
Vocative	grastatva	grastatve	grastatvāni
Accusative	grastatvam	grastatve	grastatvāni
Instrumental	grastatvena	grastatvābhyām	grastatvaiḥ
Dative	grastatvāya	grastatvābhyām	grastatvebhyaḥ
Ablative	grastatvāt	grastatvābhyām	grastatvebhyaḥ
Genitive	grastatvasya	grastatvayoḥ	grastatvānām
Locative	grastatve	grastatvayoḥ	grastatveṣu

Compound grastatva -

Adverb -grastatvam -grastatvāt