Original: Nitrogen (Latin nitrogenium, where nitrum (from Greek nitron) means "saltpetre" (see nitre), and genes means "forming") is formally considered to have been discovered by Daniel Rutherford in 1772, who called it noxious air or fixed air.
Simplified: Nitrogen is formally considered to have been discovered by Daniel Rutherford in 1772, who called it noxious gas or fixed gas.