Declension table of ?hārdvan

Masculine	Singular	Dual	Plural
Nominative	hārdvā	hārdvānau	hārdvānaḥ
Vocative	hārdvan	hārdvānau	hārdvānaḥ
Accusative	hārdvānam	hārdvānau	hārdvanaḥ
Instrumental	hārdvanā	hārdvabhyām	hārdvabhiḥ
Dative	hārdvane	hārdvabhyām	hārdvabhyaḥ
Ablative	hārdvanaḥ	hārdvabhyām	hārdvabhyaḥ
Genitive	hārdvanaḥ	hārdvanoḥ	hārdvanām
Locative	hārdvani	hārdvanoḥ	hārdvasu

Compound hārdva -

Adverb -hārdvam