User blog:Big Boss 1935/Haidaraaa!

In Metal Gear Solid Peace Walker,for co-ops communications,there is a choice to say the word Haidaraaa! I've searched and searched for the meaning of this word an I can not find anything. I've searched this site aswell as others but couldn't come up with any results. On the other hand I found the definiton of the word Haidar but as far as if they are related in meaning I have no idea. Does anyone know what this word means and if so please leave a comment,and if possible please post your source of information.