Odourless means having no smell whatever. An odourless gas, odourless and colourless, an odourless cleaner.
It matters most as a warning: carbon monoxide is odourless, colourless and tasteless, which is exactly why it kills, and natural gas has a smell added on purpose so that leaks are noticed. American spelling drops the u.
1adjectiveodourlessHaving no smell whatever.
“The cream is odourless, so it's fine for people who dislike perfume.”
odourless is a quality.
Also accepted in games: odorless
From odour + -less.
Etymology from Wiktionary, CC BY-SA