Declension table of ?hartavya

Neuter	Singular	Dual	Plural
Nominative	hartavyam	hartavye	hartavyāni
Vocative	hartavya	hartavye	hartavyāni
Accusative	hartavyam	hartavye	hartavyāni
Instrumental	hartavyena	hartavyābhyām	hartavyaiḥ
Dative	hartavyāya	hartavyābhyām	hartavyebhyaḥ
Ablative	hartavyāt	hartavyābhyām	hartavyebhyaḥ
Genitive	hartavyasya	hartavyayoḥ	hartavyānām
Locative	hartavye	hartavyayoḥ	hartavyeṣu

Compound hartavya -

Adverb -hartavyam -hartavyāt