Sounds like raging hormones. A bit more information is required like how was he raised? Only chick? With humans with a lot of interaction? Free range? Does he have any hens? Is he fighting with other cocks or just aggressive to you and humans? More info will get you more replies.
There is 1 peacock and 3 hens. He is free to range and has always been around us but is now is aggressive toward everyone who is around. If it is hormones, what can I do?