Green’s Dictionary of Slang

1. (US tramp) to rob another tramp as they sleep in the ‘hobo jungles’; later to rob a fellow criminal.

1923		N. Anderson Hobo 20: Jungle crimes include [...] (2) ‘hi-jacking,’ or robbing men at night when sleeping in the jungles.
1931		Irwin Amer. Tramp and Und. Sl. 98: HIGH JACK.–To rob. Originally, to rob a tramp or hobo, but now more generally applied to a crook who robs bootleggers of their wares, especially when the liquor has been safely smuggled through the lines of the revenue men.
1950		Goldin et al. DAUL 95/2: Hijack, v. 1. To hold up and take any truck and its contents. 2. To steal from other thieves or racketeers illegal or stolen goods.
1963		L.F. Freed Crime in S. Afr. 107: A ‘hi-jacker’ is one who robs other criminals.

2. (US) to subject to extortion.

1926

Amer. Mercury Jan. 63: The close in on a gondola or box-car full of scissorbills and by threats of violence hijack them into paying initiatory fees.

3. (US gay/prison) to rape another man.

1927		‘Jargon of the Und.’ in DN V 450: Hijack, To commit pederasty upon a boy forcibly.
1972		B. Rodgers Queens’ Vernacular 106: hijack (prison sl) to rape another man.

4. (US) to remove or move a person against their will.

1928

T.A. Dorgan in Zwilling TAD Lex. (1993) 57: I hear that a merry mucilage drummer hijacked Alfred for his twist and twirl last week.

5. (US prison) to violently rob a fellow prisoner.

1935		D. Lamson We Who Are About to Die 227: Actual hi-jacking of cons, robbery with violence, occurs only infrequently.
1936		San Quentin Bulletin in L.A. Times 6 May 7: HIJACK, to steal or extort personal belongings from fellow cons.