1. Endangering the neck; hazardous.

2. A fall, or a steep place endangering the neck.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• vreakneck,
• nreakneck,
• hreakneck,
• greakneck,
• beeakneck,
• bdeakneck,
• bfeakneck,
• bteakneck,
• brakneck,
• breaknec,
• breakenck,
• break neck,
• breake neck,
• breakoneup,
• Brokdeck,
• breackneck,
• breaknecked,
• breakeneck,
• break-necke,
• Breakonback

• breeziness,
• break camp,
• brackney,
• brazen,
• break-in,
• bracken,
• breaking,
• brackins,
• brackin,
• brackman,
• broken,
• brackens,
• break in,
• brashness,
• brueckner,
• bragan,
• brackeen,
• break wind,
• Brazan,
• Brackenridge,
• braking,
• break into.

The adjective form of the word "breakneck" is "breaknecked".

The plural form of the word "breakneck" is "breaknecks".

The singular form of the word "breakneck" is "breakneck". This word does not change in form for singular or plural usage.