In a way that does not draw attention to itself. If something is done unobtrusively, it happens, but nobody really notices it happening — and that is the point. A waiter fills your water glass unobtrusively; a good security guard stands unobtrusively near the door; a camera is placed unobtrusively in the corner of the ceiling. Notice that the word carries a small idea of *choice* inside it: usually someone is being quiet or small on purpose, out of politeness, good manners, or because they do not want to disturb people. So it is not the same as just saying 'nobody saw it'. A dropped coin lies on the floor unnoticed, not unobtrusively. The word is a bit formal and comes up much more in writing than in talking — you will meet it in novels, reviews, and articles about design or service. It is almost always positive, or at least neutral: being unobtrusive is usually a compliment, unlike 'sneakily', which says the person was hiding something bad. It can also describe things that are not people: music playing unobtrusively in a café, a small logo sitting unobtrusively in the corner of a page.

不引人注目地、低調地（服務生「默默地」把水加滿的那種感覺）。不等於「偷偷摸摸」，那是 sneakily；unobtrusively 通常帶著體貼、不打擾人的好意。