Declension table of thera

Masculine	Singular	Dual	Plural
Nominative	theraḥ	therau	therāḥ
Vocative	thera	therau	therāḥ
Accusative	theram	therau	therān
Instrumental	thereṇa	therābhyām	theraiḥ therebhiḥ
Dative	therāya	therābhyām	therebhyaḥ
Ablative	therāt	therābhyām	therebhyaḥ
Genitive	therasya	therayoḥ	therāṇām
Locative	there	therayoḥ	thereṣu

Compound thera -

Adverb -theram -therāt