day job
noun [ C ] uk/ˈdeɪ ˌdʒɒb/ us/ˈdeɪ ˌdʒɑːb/
正职（收入的主要来源，以便维持个人的其它爱好）
a job that you do to earn money so that you can do something else that you prefer but that does not pay you much money
Many actors have day jobs too. 许多演员都有演艺工作之外的日常工作。
Idiom
don't give up the day job!idiom humorous 表示认为对方做某事不在行
used for telling someone that you do not think they are very good at something
"What did you think of my singing, then?" "Er, don't give up the day job!" “你觉得我唱得怎么样？”“诶，相当业余。”