Green’s Dictionary of Slang

vamoosing n.

flight.

1862		J.R. Lowell Biglow Papers 2nd Ser. (1880) 99: When the vamosin’ come, ever to find / Nat’ral masters in front.
1885		Surrey Mirror 17 Jan. 6/3: Some people like ‘vamoosing’.
1966		G. & K. Swarthout Whichaway (1967) 22: Sure they’d vamoose while the vamoosing was good.