Green’s Dictionary of Slang

smooch v.²

(US) to steal, to pilfer; to borrow.

1842		implied in smoucher
1897		‘Mark Twain’ Tom Sawyer, Detective 43: We would be the first to tell the family [...] all about them rapscallions that done it, and about the di’monds they’ve smouched off of the corpse.
1905		L. Pound ‘Dialect Speech in Nebraska’ in DN III:i 65: smootch, v. ‘Swipe.’ ‘They smootched some turnips.’.
1920		Marvel 26 June 6: You admit you went into Pete’s cabin to steal his tobacco. Beg pardon, to smooch it, I mean?
1941		J.M. Cain Mildred Pierce (1985) 459: Then she had another drink, went over to the cash box, and smooched four ten-dollar bills.
1946		J.E. Dadswell Hey, Sucker 87: When you hear a carnie say he’s going ‘to smooch some smesh’ – he means he’s going to borrow small money.

In derivatives

smoucher (n.)

(US) a pilferer.

1842

N.Y. Aurora 7 Sept. n.p.: There were only seventeen ‘smouchers’ present, and i didn’t see them take anything.