Declension table of ?dṛdhra

Masculine	Singular	Dual	Plural
Nominative	dṛdhraḥ	dṛdhrau	dṛdhrāḥ
Vocative	dṛdhra	dṛdhrau	dṛdhrāḥ
Accusative	dṛdhram	dṛdhrau	dṛdhrān
Instrumental	dṛdhreṇa	dṛdhrābhyām	dṛdhraiḥ dṛdhrebhiḥ
Dative	dṛdhrāya	dṛdhrābhyām	dṛdhrebhyaḥ
Ablative	dṛdhrāt	dṛdhrābhyām	dṛdhrebhyaḥ
Genitive	dṛdhrasya	dṛdhrayoḥ	dṛdhrāṇām
Locative	dṛdhre	dṛdhrayoḥ	dṛdhreṣu

Compound dṛdhra -

Adverb -dṛdhram -dṛdhrāt