either 笨蛋 (ben dan) or 白痴(bai chi)
The word idiot when translated from English to Japanese is "baka," pronounced (baa-ka.)
You could just say idiot or bego.
idiot = idiota, imbécil, necio (stupid), bobo, tonto.
chu
僧 Sēng
白 = white
火 huo
熊 xiong
leng dong
犯罪.
hugnungnaniono 老
糖 【tang2】