hold your breath
hold (one's) breath
1. To intentionally stop breathing for a short period of time. I can't hold my breath for very long, so I doubt I'll be able to swim down deep enough to get the Frisbee.
2. To wait for something specific to happen. In this usage, the phrase is usually negative. The electrician said he'd be here before noon, but I won't hold my breath. She wrote a letter of complaint to the airline asking for a refund, but she isn't holding her breath.
hold your ˈbreath
1 stop breathing for a short time, for example because you are afraid of something or very anxious about something: I held my breath as the car skidded towards me.
2 be anxious while you are waiting for something that you are worried about: ‘When will you hear about your job application?’ ‘Not till next week. I’m holding my breath until then.’
3 (informal) don’t hold your breath used for telling somebody that it’s not worth waiting for something: We’ll let you know if there’s any work for you, but don’t hold your breath.