She is Voldemorts giant snake. In Buddhism and Hinduism, Nagas are a race of semi-divine snakes with great powers, so does Nagini have special powers? Voldemort promised to feed her Wormtail, then Harry. Will she get tired of his lies or unfulfilled promises and leave? Will she follow Harry's commands? Will she eat Wormtail?
'Naga' is the sanskrit word for snake. Nagini is the word for a female snake.
However, there is a tribe in Eastern India called Nagas. Also, in some Hindu mythology, there can be shape shifting snakes. Is Nagini a shape shifter? Or an animagus?
M.
"Every positive integer is one of Ramanujan's personal friends."—J. E. Littlewood.
She can't be an animagus because Voldemort used her venom to survive. We just don't know anything about her really. I suspect that she was the snake that attacked Arthur Weasley in the Ministry.
MM, thank you for the information about the root word.