thin air
noun/ˌθɪn ˈɛə(ɹ)/
1
Figuratively, Humorous, Idiomatic, Usually An unknown location; (by extension) apparent disappearance or nonexistence.
- Where did you think the exhaust would go? Into thin air?
2
Used other than figuratively or idiomatically: see thin, air, (especially, low-density air as a result of high altitude).
- You'll need to stay mindful of taking breaks, drinking water, and avoiding overexertion up here, because you're dealing with thin air at this altitude.
- Related terms
- into thin air, out of thin air, dead air, out of the blue, oxygen mask