hang from a thread

1. Literally, to be attached only by single thread, strand, or something similar. If that button is only hanging from a thread, you're bound to lose it during the course of the day. I bet she loses that tooth today—it's basically hanging from a thread at this point. Whoa, grab the wreath before it falls—it's only hanging from a thread!

2. To be perilously close to failing, dying, or resulting in a bad outcome. After the loss, their chances of getting into the championships are hanging from a thread. Her life hung from a thread as medics rushed her to the hospital. I'm warning you, Davis, you're hanging from a thread! One more slip up, and you're fired!