to depart quickly
"He raised his handgun and tried to line Reilly down its sight, but there was too much commotion around the agent and Zahed couldn't get a clean shot. Time to vamoose. With his weapon still in his grip, he leapt behind the wheel of the van, slammed it into drive, and floored it." Raymond Khoury, The Templar Salvation, 2010
About the Word:
In the 1820s and '30s, the American Southwest was roughandtumble territory the true Wild West. Englishspeaking cowboys, Texas Rangers, and gold prospectors regularly rubbed elbows with Spanishspeaking vaqueros in the local saloons, and a certain amount of linguistic intermixing was inevitable.
One Spanish term that caught on with English speakers was vamos, which means "let's go."
Cowpokes and dudes alike adopted the word, at first using a range of spellings and pronunciations that varied considerably in their proximity to the original Spanish form. But when the dust settled, the version most American English speakers were using was vamoose.