Green’s Dictionary of Slang

charlie n.1

also charley, charleyman

1. [late 17C; 19C] a watchman, a beadle [punning cant; supposedly linked to the improvement of the London watch system by Charles I, but no use of the word for 150 years afterwards is recorded].

2. [mid-19C] (US) a policeman.

3. [mid-19C] a gold watch [pun on sense 1].

In compounds

charley-ken (n.) [ken n.1 (1)]

[early 19C] (UK Und.) a watchman’s box.

charley-man (n.)

[early 19C] a watchman, a beadle.

In phrases

blind charley (n.)

[mid-19C] (US) a lamp-post.

box a charlie (v.)

[early–mid-19C] to turn over a watchman in his box.

get the best of a charlie (v.) [best v.]

[early 19C] to upset a watchman in his box, a popular ‘game’ among upper-class rowdies.