(one's) heart in (one's) mouth(redirected from their heart in their mouth)
(one's) heart in (one's) mouth
A state of extreme nervousness or anxiety. Usually used after "have" or "with." I walked across the hospital parking lot with my heart in my throat, terrified of what the doctors had to tell me. She had her heart in her throat as she stepped into the principal's office.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.