The term "Bahai" is already used in Hindi to refer to the Baha'i faith. It's not a word with a separate meaning in Hindi.
If you're looking for a Hindi word for a related concept, you could use:
* बहाई धर्म (Bahai Dharm): This literally means "Bahai religion".
* बहाई समुदाय (Bahai Samuday): This means "Bahai community".
However, it's important to note that using these words might not always be understood by everyone, as the Baha'i faith isn't as widely known in India compared to other religions.