Slang, n. [Cf. Sling.] A fetter worn on the leg by a convict. [Eng.]

Slang, n. [Said to be of Gypsy origin; but probably from Scand., and akin to E. sling; cf. Norw. sleng a slinging, an invention, device, slengja to sling, to cast, slengja kjeften (literally, to sling the jaw) to use abusive language, to use slang, slenjeord (ord = word) an insulting word, a new word that has no just reason for being.] Low, vulgar, unauthorized language; a popular but unauthorized word, phrase, or mode of expression; also, the jargon of some particular calling or class in society; low popular cant; as, the slang of the theater, of college, of sailors, etc.

Slang (?), imp. of Sling. Slung. [Archaic]

Slang, n. Any long, narrow piece of land; a promontory. [Local, Eng.] Holland.

Slang, v. t. [imp. & p. p. Slanged (?); p. pr. & vb. n. Slanging.] To address with slang or ribaldry; to insult with vulgar language. [Colloq.]

Every gentleman abused by a cabman or slanged by a bargee was bound there and then to take off his coat and challenge him to fisticuffs.
London Spectator.