Green’s Dictionary of Slang

1. (US Und., also dookey) a meal (of scraps/leftovers) given to a tramp.

1902		Times (Shreveport, LA) 12 May 3/5: His duty is to ‘mooch spangle’ (beg money) and ‘bat’ (knock at a door) for ‘dukies’ or ‘lumps’ (a lunch).
1914		Jackson & Hellyer Vocab. Criminal Sl. 30: dukie [...] Used by yeggmen and hobos. A hand-out, or donation of cold victuals to a beggar.
1944		D. Runyon Runyon à la Carte 152: Sometimes I mooch a dookey at a kitchen door.

2. (US carnival) a meal ticket; also attrib.

1927		K. Nicholson Barker I i: chris: What’s a dukie? nifty: Dukie! Meal ticket.
1949		Monteleone Criminal Sl. (rev. edn) 76: dukie book The meal ticket book.

3. (US, also dukey) a light meal, esp. that carried to work by a labourer or factory worker.

1926		E.P. Norwood Other Side of the Circus 754: ‘What did the man mean by a “dukie”?’John wanted to know. ‘That’s circus slang for a lunch’ [...] Ollie Webb puts up box lunches. We call them ‘dukies.’ Of course, ’most any elephant will grab a dukie of hay.
1962		C. Clausen I Love You Honey, But the Season’s Over 62: Dukeys were lunch boxes given out by the circus.

4. (US prison) a sandwich.

1962

Ragen & Finston World’s Toughest Prison 797: dukie – A sandwich.