Declension table of ?tantvagra

Neuter	Singular	Dual	Plural
Nominative	tantvagram	tantvagre	tantvagrāṇi
Vocative	tantvagra	tantvagre	tantvagrāṇi
Accusative	tantvagram	tantvagre	tantvagrāṇi
Instrumental	tantvagreṇa	tantvagrābhyām	tantvagraiḥ
Dative	tantvagrāya	tantvagrābhyām	tantvagrebhyaḥ
Ablative	tantvagrāt	tantvagrābhyām	tantvagrebhyaḥ
Genitive	tantvagrasya	tantvagrayoḥ	tantvagrāṇām
Locative	tantvagre	tantvagrayoḥ	tantvagreṣu

Compound tantvagra -

Adverb -tantvagram -tantvagrāt