doesn't come off; hasn't been issuedDepending on context, it can mean that something will not come off or fall off, that an order or announcement has not been issued, or that someone cannot get words out. The form 떨어져 is informal; the polite form is 안 떨어져요.
KO: 긴장해서 입이 안 떨어져.
EN: I'm so nervous that I can't get the words out.