painless
adj. 无痛的；不痛的
例句
The operation itself is a brief, painless procedure.
手术本身是一个短暂、无痛的过程。
《柯林斯英汉双解大词典》
Acupuncture treatment is gentle, painless, and relaxing.
针灸治疗很温和，无痛，也很放松。
The treatment is painless.
这种治疗无疼痛。
《牛津词典》
