Declension table of tapasya

Masculine	Singular	Dual	Plural
Nominative	tapasyaḥ	tapasyau	tapasyāḥ
Vocative	tapasya	tapasyau	tapasyāḥ
Accusative	tapasyam	tapasyau	tapasyān
Instrumental	tapasyena	tapasyābhyām	tapasyaiḥ tapasyebhiḥ
Dative	tapasyāya	tapasyābhyām	tapasyebhyaḥ
Ablative	tapasyāt	tapasyābhyām	tapasyebhyaḥ
Genitive	tapasyasya	tapasyayoḥ	tapasyānām
Locative	tapasye	tapasyayoḥ	tapasyeṣu

Compound tapasya -

Adverb -tapasyam -tapasyāt