Odourless means having no smell. A liquid, a gas, a cream, or a room can be odourless: your nose gets nothing. British English writes it this way; American English writes odorless. Same adjective, different letters. In shops it can be a promise — an odourless cream will not leave a smell on your skin. In science it can be a warning. A gas that is colourless and odourless gives you no sight and no smell to go on, so you may not know it is there. Daily English sometimes just says “it has no smell.” Odourless is the tidier, slightly school-and-label word for that fact. It is about the nose, not about taste, even when a Chinese label nearby says 無味.

無臭的、沒有氣味的（英式拼法）。「無味」常被拿來當對譯，但那也常指沒有味道。