Green’s Dictionary of Slang

(US Und.) to steal; thus jump-out n., an act of theft.

1903

H. Hapgood Autobiog. of a Thief 39: He is greatly handicapped, and can not ‘jump out’ (steal) with any boldness. [Ibid.] 78: On my very first jump-out I got a fall, but the copper was open to reason.