Translation guide
The main job or profession that someone does, especially as opposed to side jobs or hobbies.
principal occupation
The primary work that someone does for a living, often in contrast to part-time or secondary work.
The most common and natural way to say 'principal occupation'. It implies the main job that provides one's primary income or identity.
本業 (ほんぎょう) is the most common and neutral term for one's main job. 本職 (ほんしょく) often implies professional status or expertise, and can be used to distinguish a professional from an amateur. In many contexts they are interchangeable, but 本職 can sound more formal or emphasize skill.
What is your principal occupation?
Polite form with honorific prefix ご.
彼の本業は教師です。
His principal occupation is teaching.
My main job is so busy I can't manage my side business.
Similar to 本業, but often emphasizes one's professional identity or expertise. Can also mean 'professional' as opposed to amateur.
He is a professional chef (that's his principal occupation).
A more literal translation, often used in formal or written contexts like forms or surveys.
Please fill in your principal occupation.
A somewhat literary or traditional term for one's livelihood or trade. It carries a nuance of the work that sustains one's life.
Farming is his principal occupation.
Writing is his principal occupation.