One's courage or hope fails; one is very disappointed or dejected. For example, An hour before the picnic I heard thunder and my heart sank. This expression was first recorded in 1605 but was preceded in the 15th century by one's heart is at one's heels or in one's hose or in one's shoes .

What does the phrase my heart sank mean?

Definition of one's heart sinks

—used to say that someone becomes sad or disappointed about something My heart sank when I saw the pained expression on her face.

Is my heart sank an idiom?

Meaning of Idiom 'One's Heart Sinks' If your heart sinks you are disappointed and discouraged; to become depressed; to lose hope; to become anxious and pessimistic.