Green’s Dictionary of Slang

(US) to steal.

1856		B.H. Hall College Words (rev. edn) 435: smouge. [...] to obtain without leave.
1865		G.A. Sala My Diary in America I 240: Detected in ‘smouching-a-tom-cod’ from the altar of the Chinese temple in San Francisco, he was disgracefully expelled from the Golden State.
1872		‘Mark Twain’ Roughing It 135: The Mormon Bible is rather stupid [...] it is ‘smouched’ from the New Testament and no credit given.
1882		Amer. Comic Etiquette for Children in Ware (1909) 227/2: While grace is being said at the table, children should know that it is a breach of good breeding to smouge fruit-cakes just because their parents’ heads are bowed down.
1884		(con. c.1840) ‘Mark Twain’ Huckleberry Finn 231: It ’ll be a long day before he gives anybody another chance to smouch it from him.
1896		‘Mark Twain’ Tom Sawyer, Detective Ch. VI: All about them rapscallions that done it, and about the di’monds they’ve smouched off of the corpse.
1900		E.H. Babbitt ‘College Words and Phrases’ in DN II:i 61: smouge, v. To crib.
1905		L. Pound ‘Dialect Speech in Nebraska’ in DN III:i 65: smouge, v. (1) Filch, or wring out of; (2) sneak in, or through, dishonorably; encroach on. ‘I smouged a piece of goods’; ‘He smouged the chaimanship’.