1. (informal) to act or begin too soon or without due caution 
2. To begin a race too soon, before the starting gun goes off

Derived forms: jumped the gun

• clonic
• clonidine
• cloning
• clonk
• clonus
• cloot
• Clootie
• Cloots
• clop
• clopidogrel bisulfate
• clopping
• Clorox
• close
• close at hand
• close call
• close corporation
• close harmony
• close in
• close off
• close order
• close quarters
• close set
• close shave
• close support
• close supporting fire