your normal job which you earn most of your money from doing, especially as opposed to another interest 正职,白天的工作〔相对于兼职〕
I’d love to be a professional writer, but I’m not giving up my day job just yet.
我想成为职业作家,但我目前还不打算辞去正职。
Examples from the Corpus
day job• Bennett kept his day job and concentrated on his main art pursuit, collages.• He has kept his day job.• Now he's prepared to give up his day job to chase the dream.• Don't give up your day job said some one.