Declension table of ?siddhasiddha

Neuter	Singular	Dual	Plural
Nominative	siddhasiddham	siddhasiddhe	siddhasiddhāni
Vocative	siddhasiddha	siddhasiddhe	siddhasiddhāni
Accusative	siddhasiddham	siddhasiddhe	siddhasiddhāni
Instrumental	siddhasiddhena	siddhasiddhābhyām	siddhasiddhaiḥ
Dative	siddhasiddhāya	siddhasiddhābhyām	siddhasiddhebhyaḥ
Ablative	siddhasiddhāt	siddhasiddhābhyām	siddhasiddhebhyaḥ
Genitive	siddhasiddhasya	siddhasiddhayoḥ	siddhasiddhānām
Locative	siddhasiddhe	siddhasiddhayoḥ	siddhasiddheṣu

Compound siddhasiddha -

Adverb -siddhasiddham -siddhasiddhāt