Declension table of ?avastra

Masculine	Singular	Dual	Plural
Nominative	avastraḥ	avastrau	avastrāḥ
Vocative	avastra	avastrau	avastrāḥ
Accusative	avastram	avastrau	avastrān
Instrumental	avastreṇa	avastrābhyām	avastraiḥ avastrebhiḥ
Dative	avastrāya	avastrābhyām	avastrebhyaḥ
Ablative	avastrāt	avastrābhyām	avastrebhyaḥ
Genitive	avastrasya	avastrayoḥ	avastrāṇām
Locative	avastre	avastrayoḥ	avastreṣu

Compound avastra -

Adverb -avastram -avastrāt