Just like if you call some Sikh guy a gyaani, he will get offended. But in reality gyaani in sanskrit means a guy with knowledge.
Sikhs don't get offended if you call them Gyanni !!!!! One of India's president was Gyani Zial Singh !!!! But yes it is a bit "old fashioned" these days and just like calling a young muslim a "maulana" is going to generate a response from your muslim friend .....