Declension table of ?rīvya

Neuter	Singular	Dual	Plural
Nominative	rīvyam	rīvye	rīvyāṇi
Vocative	rīvya	rīvye	rīvyāṇi
Accusative	rīvyam	rīvye	rīvyāṇi
Instrumental	rīvyeṇa	rīvyābhyām	rīvyaiḥ
Dative	rīvyāya	rīvyābhyām	rīvyebhyaḥ
Ablative	rīvyāt	rīvyābhyām	rīvyebhyaḥ
Genitive	rīvyasya	rīvyayoḥ	rīvyāṇām
Locative	rīvye	rīvyayoḥ	rīvyeṣu

Compound rīvya -

Adverb -rīvyam -rīvyāt