What does Rishi mean?
From the Sanskrit ऋषि (ṛṣi), 'a seer, sage, inspired poet' — the title of the sages to whom the Vedic hymns were revealed. A firmly established classical word.
What does Vivaan mean?
Commonly glossed as 'the first rays of the morning sun' and associated with Surya (the sun). It is a modern Sanskrit-derived name; the popular claim that it is an epithet of Krishna rests on weak sources, so treat that association cautiously.