The definition of cojones is a vulgar Spanish word that refers to a man's testicles, and is a slang term for having courage.
A man's testicles are an example of cojones.
When you wish to tell someone to get up the courage to do something, this is an example of a time when you might advice him to show some cojones.
Origin of cojones
- Spanish pl. of cojón testicle from Vulgar Latin cōleō, cōleōn- from Latin cōleī testicles
From American Heritage Dictionary of the English Language, 5th Edition