Declension table of ?chātavya

Neuter	Singular	Dual	Plural
Nominative	chātavyam	chātavye	chātavyāni
Vocative	chātavya	chātavye	chātavyāni
Accusative	chātavyam	chātavye	chātavyāni
Instrumental	chātavyena	chātavyābhyām	chātavyaiḥ
Dative	chātavyāya	chātavyābhyām	chātavyebhyaḥ
Ablative	chātavyāt	chātavyābhyām	chātavyebhyaḥ
Genitive	chātavyasya	chātavyayoḥ	chātavyānām
Locative	chātavye	chātavyayoḥ	chātavyeṣu

Compound chātavya -

Adverb -chātavyam -chātavyāt