Declension table of ?śastra

Masculine	Singular	Dual	Plural
Nominative	śastraḥ	śastrau	śastrāḥ
Vocative	śastra	śastrau	śastrāḥ
Accusative	śastram	śastrau	śastrān
Instrumental	śastreṇa	śastrābhyām	śastraiḥ śastrebhiḥ
Dative	śastrāya	śastrābhyām	śastrebhyaḥ
Ablative	śastrāt	śastrābhyām	śastrebhyaḥ
Genitive	śastrasya	śastrayoḥ	śastrāṇām
Locative	śastre	śastrayoḥ	śastreṣu

Compound śastra -

Adverb -śastram -śastrāt