Green’s Dictionary of Slang

1. (US) a boy, esp. when used as derog. form of address, implying youth, insignificance etc.

1839		C.F. Briggs Adventures of Harry Franco II 189: ‘Speak louder, Bub,’ said one of the vice presidents encouragingly.
1842		Whip & Satirist of NY & Brooklyn (NY) 8 Jan. n.p.: ‘I’ll keep it [i.e. money] for you, bub’.
1855		Life in Boston & N.Y. (Boston, MA) 14 Apr. n.p.: At about 11 o’clock the bubs took up a ‘Camptown’ to buy a quart of r.g., and soon raised twenty-five cents.
1872		‘Mark Twain’ Roughing It 51: The cayote turns, [...] and [...] seems to say: ‘Well, I shall have to tear myself away from you, bub – business is business.’.
1884		G.W. Peck Peck’s Boss Book 159: Come, bub, we will go down to the candy store.
1896		Indian Advocate (Sacred Heart, OK) 1 July 78/2: Bub, I’m looking for a youth about two heads taller than you.
1907		S.E. White Arizona Nights 111: Sorry to disturb your repose, bub.
1910		O. Johnson Varmint 13: Say, Bub [...] You’re goin’ to have a great time at this little backwoods school.
1911		E. Dyson ‘An Amorous Boy’ in Benno and Some of the Push 175: A stinker boy’s a bub et school what won’t fight nothin’, smooges t’ the teachers, narks everythin’, ’n’s clean an’ pretty alwiz.
1922		in R. Butterfield Sat. Eve. Post Treasury (1954) 1 July 267: Open the door, bub, so’s we can hear.
1933		J. Conroy Disinherited 182: What you crying for, bub?
1944		C.B. Davis Rebellion of Leo McGuire (1953) 13: ‘Look, bub,’ the policeman said, ‘Why aren’t you in school today?’.
1949		in C. Hamilton Men of the Und. 179: Congratulations, bub, you’ve won a soap-bubble pipe!
1955		J.P. Donleavy Ginger Man (1958) 87: Say, bub, you’re a moral leper.
1957		‘Weldon Hill’ Onionhead (1958) 224: Don’t call me bub, you jerk.
1959		A. Burgess Beds in the East (1972) 490: ‘Where do you keep your cash, bub?’ asked Idris hoarsely. His American was better than Hassan’s English.
1968		T. Wolfe Electric Kool-Aid Acid Test (1969) 37: Well, bub, I dunno, I cain’t exactly go along with you there.
1977		L. Heinemann Close Quarters (1987) 139: What’ll ya have, bub?
1981		W. Boyd ‘Not Yet, Jayette’ in On the Yankee Station (1982) 19: Oh he left five minutes ago, bub.
1991		B Hamper Rivethead (1992) 196: Go inseminate a tractor, bub.
1999		(con. 1916) R Doyle A Star Called Henry (2000) 131: You’re not locking me out, bub, I said.
2001		S. King Dreamcatcher 470: Push the buttons, bub.
2009		J. Stahl Pain Killers 76: C’mon, bub, what are you doing in there?
2012		(con. 1954) ‘Jack Tunney’ Tomato Can Comeback [ebook] Kolodzei made a cutting motion with his hand [...] ‘Radio silence, bub’ [...] ‘You just keep those drinks comin’ bub, and I’ll tell you all kindsa stuff’.

2. (Aus. / N.Z. ) a baby.

1904		‘Dads Wayback’ in Sun. Times (Sydney) 14 Aug. 1/6: ‘When we’s bubs, we spends most o’ our time sleepin’ .
1905		N.Z. Observer 4 Feb. 5/1: [caption] Little Bub: Mamma my stomach aches.
1986		C. Bowles G’DAY 44: She’s too young dava bub. Should’ve adder boiler scraped when she adder chance.
2001		(con. 1945–6) P. Doyle Devil’s Jump (2008) 203: Mid afternoon, May and cec took the bub out for a stroll.
2017		T. Spicer Good Girl Stripped Bare 240: ‘It’s bad timing with a bub on the way’.

3. (US campus) a person devoid of redeeming qualities.

1989		P. Munro Sl. U. 46: That guy has no friends because he is such a bub.
2000		F. Kellerman Stalker (2001) 216: The bastard was pretending not to see her. You’re not going anywhere, bub.

4. (Aus.) a kindergarten-age child.

2020

G. Disher Consolation 343: ‘I live for the day I’m just a nobody again, back teaching the bubs’.