The affix ghañ comes after the root iṅ 'to study'.,
This debars अच् 3.3.56. As अधि+ इ + घञ् = अधि + ऐ + अ = अध्याय 'a lesson or lecture'; उपाध्यायः (उपेत्यास्मादधीते) 'a teacher'.
Vart:- When the word to be formed is related to the verb इङ् as an ablative, the word is feminine also and optionally takes the affix ङीष्. As उपेत्याधीयतेऽस्या = उपाध्याया or उपाध्यायी 'a female teacher'.
Vart:- The affix घञ् comes after the root शॄ when the word so formed means 'wind', 'color', or 'cessation'. As शारः 'wind', 'green colour' &c. गौरिवाकृतमीशारः प्रायेण सिशिरे कृशः ।,