Green’s Dictionary of Slang

willie n.²

(US) lunchmeat.

1926		(con. 1918) L. Nason Chevrons 48: Can you let me have a can of hardtack and some canned willy? [Ibid.] 316: Who wants to bet me we get canned willie?
1927		(con. WWI) C. Venable ‘An Argonne Raid’ in Mason Fighting American (1945) 481: How about that can of Willie you pinched off that dead machine-gunner?

In phrases

willie lunchmeat (n.) (also sammy lunchmeat, willie lump-lump) [generic use of proper name + the stolidity and density of SE lunchmeat/lump; note the US comedian Red Skelton’s ‘character’, the drunken Willie Lump-Lump]

(US Und.) a fool; also attrib.

1984		J. Nazel Delta Crossing 87: I’m no Willie Lunchmeat idiot that is going to let himself be railroaded!
1985		T.R. Houser Central Sl. 46: wille/sammy lunchmeat A sissy A pooh butt.
1992		Bentley & Corbett Prison Sl. 37: Willie Lump Lump also Willie Lunch Meat An idiot.
2015		P. Beatty Sellout (2016) 40: Another Willie Lump Lump witha six-line résumé rife with spelling errors.