Green’s Dictionary of Slang

1. (also tommy boy) used as a term of address to a young boy whose real name is unknown.

1915		Wodehouse Psmith Journalist (1993) 216: ‘Editor in, Tommy?’ inquired the man.
1936		(con. 1895) T. O’Reilly Tiger of the Legion 62: ‘Well, well! The principal bout of the evening, eh? Two-pennorth of Ha’pence, versus Champion Brown! You’d better go home to your mother, Tommy!’ .
1949		Monteleone Criminal Sl. (rev. edn) 241: tommy boy A young boy.

2. a pimp [? generic use of proper name].

1923

J. Manchon Le Slang.