Entry 3 senses · 2 variants Webster, 1913

Breakneck

/brāk'-nĕkˌ/ · Break·neck · IPA /ˈbɹeɪkˌnɛk/

01 n. A fall that breaks the neck.

1.
A fall that breaks the neck.
2.
A steep place endangering the neck.

02 a. Producing danger of a broken neck; as, breakneck speed.

1.
Producing danger of a broken neck; as, breakneck speed.