Declension table of śāstṛ

Masculine	Singular	Dual	Plural
Nominative	śāstā	śāstārau	śāstāraḥ
Vocative	śāstaḥ	śāstārau	śāstāraḥ
Accusative	śāstāram	śāstārau	śāstṝn
Instrumental	śāstrā	śāstṛbhyām	śāstṛbhiḥ
Dative	śāstre	śāstṛbhyām	śāstṛbhyaḥ
Ablative	śāstuḥ	śāstṛbhyām	śāstṛbhyaḥ
Genitive	śāstuḥ	śāstroḥ	śāstṝṇām
Locative	śāstari	śāstroḥ	śāstṛṣu

Compound śāstṛ -

Adverb -śāstṛ