Translation

副業的な趣味 / 本業以外の活動 / 余技

Meaning

An avocation is an activity someone pursues seriously outside their main job, often for pleasure. It is more formal than hobby and often suggests skill, commitment, or a long-term interest.

Examples

• 彼の本業は会計士ですが、写真が本格的な趣味です。
  His profession is accounting, but photography is his avocation.
• 退職後、彼女は園芸を本業以外の活動として楽しみました。
  After retirement, gardening became her avocation.