An anti-perspirant is a product, usually a roll-on or a spray, that you put under your arms to slow down sweat. It does not only cover smell; it tries to block the sweat from coming out, often with a metal salt that makes the tiny openings in the skin smaller for a while. People use it in the morning, before a hot day or a nerve-wracking talk. It is an everyday shop word, not a doctor's word, though the idea is medical enough. Though actually, many bottles are both anti-perspirant and deodorant at once, so the label looks like one job when it is two: one job is keeping you drier, the other is making the smell quieter. Some people avoid it because they do not like the idea of blocking sweat; that is a preference, not a rule about the meaning.

止汗劑（和只去味的「體香劑」不一樣）。