ˈsneaksmanCant. [f. sneak n.or v.] (See quots. 1812, 1859.) 1812J. H. Vaux Flash Dict., Sneaksman, a man or boy who goes upon the sneak.1834Ainsworth Rookwood iii. v, There was no such sneaksman..going.1859Slang Dict. 97 Sneaksman, a shoplifter; a petty cowardly thief.