Green’s Dictionary of Slang

1. a prostitute or a thief’s female companion, esp. one who decoys and then robs drunks.

1879		‘Autobiog. of a Thief’ in Macmillan’s Mag. (London) XL 502: It was at one of these places down Whitechapel I palled in with a trip and staid with her until I got smugged.
1887		‘Dagonet’ ‘A Plank Bed Ballad ’ in Referee 12 Feb. n.p.: My trip – cuss the day as I seen her – / She sold off my home to some pals in her mob, / For a couple of foont and ten deener.
1928		M.C. Sharpe Chicago May (1929) 260: Gun Molls, or Trips — women who steal from men in the street, or carry guns.
1938		(ref. to 1910s) F.D. Sharpe Sharpe of the Flying Squad 165: Flash women decoys, known in the business as ‘Trips,’ made the acquaintance of seamen.

2. see trick n.¹ (3)