Declension table of ?siddhakārya

Neuter	Singular	Dual	Plural
Nominative	siddhakāryam	siddhakārye	siddhakāryāṇi
Vocative	siddhakārya	siddhakārye	siddhakāryāṇi
Accusative	siddhakāryam	siddhakārye	siddhakāryāṇi
Instrumental	siddhakāryeṇa	siddhakāryābhyām	siddhakāryaiḥ
Dative	siddhakāryāya	siddhakāryābhyām	siddhakāryebhyaḥ
Ablative	siddhakāryāt	siddhakāryābhyām	siddhakāryebhyaḥ
Genitive	siddhakāryasya	siddhakāryayoḥ	siddhakāryāṇām
Locative	siddhakārye	siddhakāryayoḥ	siddhakāryeṣu

Compound siddhakārya -

Adverb -siddhakāryam -siddhakāryāt