Green’s Dictionary of Slang

an expression of praise for anything or anyone delightful, usu. delicious food.

1865		in B.L. Ridley Battles and Sketches of the Army of Tennessee (1906) 458: General S. succeeds in having a barrel of peach brandy [...] given him by Mr. Vaughn. Yum! yum!
1878		Burlington Hawk Eye (IA) in Irish Monthly VI 688: How we would like to get hold of the man [...] Alone. In the woods, with a revolver in our hip-pocket. Revenge is sweet; yum, yum, yum .
1880		Morehouse Clarion (Bastrop, LA) 25 June 4/3: Oh, don’t darling! you mustn’t! Yum-yum!
1882		G.W. Peck Peck’s Sunshine 108: He [a cockroach] walks all over the cake [...] stands on his head and seems to say, ‘Yum, yum.’.
1883		Bristol Magpie 11 Jan. 13/2: Squeeze her till the blushes come, / Shut your eyes and—yum-yum-yum!
1890		Dead Bird (Sydney) 6 Sept. 1/2: We do not believe in boy-cotting; girl-cotting is more in our line, you bet—; ’specially when they’re juicy, plump, and tender. Yum! yum!! yum!!!
1899		Kipling ‘The Last Term’ Complete Stalky & Co. 274: Pretty lips – sweeter than – cherry or plum, / Always look – jolly and – never look glum; / Seem to say – Come away. Kissy! – come, come! / Yummy-yum! Yummy-yum! Yummy-yum-yum!
1899		Monroe City Democrat (MO) 25 May 1/5: Yum, yum, but the Dude is a warm number.
c.1908		Harrington & Powell [perf. Marie Lloyd] The Directoire Girl 🎵 All the London Johnnies and their country cousins / And they all said, ‘Yum Yum’ I really was a big success.
1915		Day Book (Chicago) 20 Dec. 11/1: Dis is what dey’s goin’ to have for eats. Toikey — yum yum.
1922		Joyce Ulysses 167: Ravished over her I lay, full lips full open, kissed her mouth. Yum.
1945		Botkin Lay My Burden Down 161: The biscuits was yum, yum, yum to me.
1954		Beano 27 Mar. n.p.: Yum! Yum! The boys are going to enjoy this!
1967		F. Sargeson Hangover 34: ‘Cornish pasty,’ she said. ‘Yum yum.’.
1977		A. Ayckbourn Just Between Ourselves II ii: marjorie: I’ve got you a nice chop. dennis: Lovely. Yum yum.
1982		Beano 16 Jan. 8: Yum! I’d just love some hot buttered toast.
1991		Dandy Comic Library No. 210 11: Yum-yum. Delicious!
2004		J. Ellroy ‘Hollywood Fuck Pad’ in Destination: Morgue! (2004) 237: She stone fox – yum, yum!
2024		J. Meades Empty Wigs (t/s) 517: He knew immediately. I knew too. I thought yum yum, yes indeedy.