〔選択が自由の〕optional;〔自発的な〕voluntary
- 寄付は随意である
- Contributions are voluntary.
- 今切符を買うか買わぬかはご随意に
- It's up to you whether you buy a ticket now or not.
- 彼の随意にさせてあげなさい
- Let him do as he pleases./Let him have his way.
- ここにある物はご随意にお使いください
- These things are at your disposal.