Declension table of ?hartavya

Masculine	Singular	Dual	Plural
Nominative	hartavyaḥ	hartavyau	hartavyāḥ
Vocative	hartavya	hartavyau	hartavyāḥ
Accusative	hartavyam	hartavyau	hartavyān
Instrumental	hartavyena	hartavyābhyām	hartavyaiḥ hartavyebhiḥ
Dative	hartavyāya	hartavyābhyām	hartavyebhyaḥ
Ablative	hartavyāt	hartavyābhyām	hartavyebhyaḥ
Genitive	hartavyasya	hartavyayoḥ	hartavyānām
Locative	hartavye	hartavyayoḥ	hartavyeṣu

Compound hartavya -

Adverb -hartavyam -hartavyāt