errand boynnoun: Refers to person, place, thing, quality, etc.
(boy who carries messages, go-between)
跑差 pǎo chāi
供差遣的童仆 gōng chāi qiǎn de tóng pú
Don't ask me to pass your messages: I'm not your errand boy. I had the title of Assistant to the President, but the truth is, I was just an errand boy.