职业(zhí yè) - occupation, profession, professional in Mandarin

职业 (zhí yè) is your occupation in the form-filling sense: the profession you belong to rather than the particular job you turn up to. It is what goes in the box on a visa application.

Put in front of a noun it means professional as opposed to amateur: 职业运动员, 职业球队, 职业习惯. That is a genuine second life for the word and worth learning as a separate habit.

The trap is 工作. If you want to say I am looking for a job, I am going to work, my job is tiring, use 工作 every time. 职业 is the category; 工作 is the daily thing. Also keep it apart from 专业, which is a university major or a field of specialism.