Green’s Dictionary of Slang

bucko n.1

[buck n.1 + -o sfx (1), thence naut. jargon bucko, an overbearing ship’s officer, who enforces his will through (threats of) violence, usu. as bucko mate]

1. a bully, a blustering swaggerer.

[US]‘Frederick Benton Williams’ (H.E. Hamblen) On Many Seas 317: Every man aboard, from the captain down, prides himself on being a ‘bucko,’ — a fighter, that is to say.
[US]F.P. Dunne Mr Dooley in Peace and War 208: He was a fine bucko.
[US]P. Kyne Cappy Ricks 114: I’d make that bucko suffer.
[US]R.E. Howard ‘Sailors’ Grudge’ Fight Stories Mar. [Internet] I was a fighting man [...] the terror of all first mates and buckos afloat.
[[US]R.E. Howard ‘TNT Punch’ Action Stories Jan. [Internet] A bucko, as you likely know, is a hard-case mate, who punches his crew around].
[US]J.E. Macdonnell Jim Brady 71: You shouldn’t have much to worry about if any of those Grammar buckos try to do you over.
[UK]J. McClure Spike Island (1981) 274: This is when the fights start. This is what they’re looking for, these local buckos — so-called supporters, but we don’t recognise them as such.

2. a general term of address, e.g. my bucko.

[US]A. Trumble Mott Street Poker Club 27: ‘Ah! me bucco, so I have ye at last’.
[US]F.P. Dunne in Schaaf Mr Dooley’s Chicago (1977) 42: Well Frank me bucko, an’ how ar-re ye?
[US]S.E. White Arizona Nights 116: ‘What?’ says I. ‘Elucidate, my bucko.’.
[US]F. Packard Adventures of Jimmie Dale (1918) I v: This ain’t any police job, my bucko.
[Ire]B. Duffy Rocky Road 202: ‘I have you at last, me bucko!’ said the policeman.
[US]J. Conroy World to Win 67: And why not, I ask ye, me bucko?
[Ire]‘Myles na gCopaleen’ Faustus Kelly in ‘Flann O’Brien’ Stories & Plays (1973) 124: You’re roight, me bucko.
[UK]J. Curtis Look Long Upon a Monkey 38: I understand you, me bucko.
[UK]P. Larkin letter 5 Mar. in Thwaite Sel. Letters (1992) 383: Next sign will be the heavy tread of the British law enforcement officer, come along o me, my bucko, we know your sort.
[Ire]C. Brown Down All the Days 88: You’re bloody Darby-and-Joan now, me bucko.
[US]C. Hiaasen Skin Tight 26: Not together, bucko, trust me.
[US]A. Rodriguez Spidertown (1994) 48: Spider he tol’ me I get my shit at midnight an’ it’s already [...] Twelve-thirty, bucko.
[US]S. King Dreamcatcher 518: Lovely to hear you, bucko!
[US]C. Hiaasen Nature Girl 232: I’ve seen her in action, bucko.

3. a (spirited young) man.

[US]O.R. Cohen ‘The Wild Man’ All-Story 28 Aug. [Internet] I wasn’t surprised to see the bucko share catching honors with Thomson.
[UK]Hall & Niles One Man’s War (1929) 329: Talked to two young buckos from the 95th Squadron.
[Ire]Joyce Ulysses 306: That’s the bucko that’ll organize her, take my tip.
[US] ‘The Killer’ in Lomax & Lomax Amer. Ballads and Folk Songs 403: I’m a ra’rin’, flarin’ bucko, not afraid to play my hand.
[Ire]‘Flann O’Brien’ At Swim-Two-Birds 227: A game bucko if you like. Be damned but he wouldn’t die!
[UK]B. MacMahon Children of the Rainbow 1: Ah, the lovely world of youth and soon enough the buckos would be brought to heel!
[Ire](con. 1890–1910) ‘Flann O’Brien’ Hard Life (1962) 70: In God’s name, he said loudly, what is that bucko up to?
[UK]J. McClure Spike Island (1981) 17: For although Ireland still has its dashing young ‘buckos’ the word has almost disappeared from everyday use in Liverpool.
[Ire]J. O’Connor Secret World of the Irish Male (1995) 83: Them buckos look after their own.