Declension table of ?ṛṣu

Masculine	Singular	Dual	Plural
Nominative	ṛṣuḥ	ṛṣū	ṛṣavaḥ
Vocative	ṛṣo	ṛṣū	ṛṣavaḥ
Accusative	ṛṣum	ṛṣū	ṛṣūn
Instrumental	ṛṣuṇā	ṛṣubhyām	ṛṣubhiḥ
Dative	ṛṣave	ṛṣubhyām	ṛṣubhyaḥ
Ablative	ṛṣoḥ	ṛṣubhyām	ṛṣubhyaḥ
Genitive	ṛṣoḥ	ṛṣvoḥ	ṛṣūṇām
Locative	ṛṣau	ṛṣvoḥ	ṛṣuṣu

Compound ṛṣu -

Adverb -ṛṣu