Green’s Dictionary of Slang

plug n.3

[Du. plug, a worn-out horse]

1. (Aus./N.Z.) a sturdy horse, standing about 15 hands high, that is sufficient for the work required.

[UK]W.T. Hornaday Two Years in Jungle 284: The horses were large and rather raw-boned Australian ‘plugs’, well qualified for the work they had to do, and, as we had a fresh pair for every six miles .

2. (US) an incompetent or undistinguished person; also attrib.

[US]Ladies’ Repository (N.Y.) Oct. VIII:37 316/2: Plug, [...] a nickname for a homely man.
[US] in J.D. Billings Hardtack and Coffee 72: Next came General Meade, a slow old plug, / Hurrah! Hurrah! / For he let them get away at Gettysburg.
[US]‘Bill Nye’ Bill Nye and Boomerang 50: Let us ignore the death of every plug who claims to be a James’ boy.
[US]C.L. Cullen Tales of the Ex-Tanks 93: Side-aisle plugs who looked like brickyard hands.
[US]A. Baer Two & Three 23 Apr. [synd. col.] Many a manager who buys a player to plug that gap in the infield discovers that he has bought a plug, all right.
[US]S. Lewis Main Street (1921) 175: I don’t want to be a plug general practitioner all my life.
[US]A.J. Barr Let Tomorrow Come 39: Well, me an’ a plug – K.Y.; I don’t know his real handle.
[US]L.W. Merryweather ‘Argot of an Orphans’ Home’ in AS VII:6402: plug, n. A clumsy person.
[US](con. 1917) S.J. Simonsen Soldier Bill 45: The young fellows joining the army nowadays can take the girls away from us plugs; there is something wrong with us.
[US]Redbook Mar. 48/2: You—you broken reed! You doormat! Old steady, unimaginative, dumb plug! [DA].

3. (US) a worn-out old horse.

[US]O.H. Oldroyd Lincoln’s Campaign (1896) 171: There’s an old plow ‘hoss’ whose name is ‘Dug,’ [...] he’s short and thick and a regular ‘plug’ [DA].
[US]‘Mark Twain’ Roughing It 179: I know that horse [...] he is, without the shadow of a doubt, a Genuine Mexican Plug!
[US]‘Bill Nye’ Bill Nye and Boomerang 17: He jabs the Mexican spurs into the foamy flank of his noble cayuse plug.
[US]Kirk Munroe Forward, March 29: You see she’s a Mexican—what Mark Twain would call a ‘genuine Mexican plug’.
[US]S. Ford Shorty McCabe 138: It didn’t seem to worry Jarvis any more’n if he was drivin’ a pair of mail-wagon plugs.
[US]H. Green Maison De Shine 218: A coupla acrobats what lived here got me to put the hull roll on some old plug.
[US]G. Bronson-Howard Enemy to Society 7: So long, stick-in-the-mud. Needn’t stop your old plugs fer me.
[US]F.S. Fitzgerald This Side of Paradise in Bodley Head Scott Fitzgerald III (1960) 225: You can leave your old plug in our stable.
[US](con. 1900) L. Riggs Green Grow the Lilacs I iii: Plug or no plug, you mighta tied him some’eres else.
[US]C.J. Lovell ‘The Background of Mark Twain’s Vocab.’ in AS XXII:2 95: plug. A worthless horse.
[US]‘Blackie’ Audett Rap Sheet 41: There was two fresh young saddle horses tied to the rail outside the barn. The old plugs was gone.
[US]E. Tidyman Shaft 1: A long purple coat that looked like a blanket on a Central park plug.

4. (US) a fellow, a person, a chap.

[US]J. Flynt Tramping with Tramps 278: I’m always willing to be square to a square plug [fellow].
[US]Number 1500 Life In Sing Sing 251: Plug. A fellow.
[US]C. M’Govern By Bolo and Krag 201: ‘The gentlemens Americans wish find gold,’ the grey-haired old plug had told me.
[UK]D. Lowrie My Life in Prison 47: He seems t’ be a pretty good sort o’ plug.
[US]P. & T. Casey Gay-cat 302: Gee, guy, gun, mug, plug, stiff, etc.—a fellow.
[US]Monteleone Criminal Sl. (rev. edn).

5. (US campus) a hard-working student.

[US]E.H. Babbitt ‘College Words and Phrases’ in DN II:i 49: plug, n. A hard student.

6. (Can.) an unpleasant person.

[US]E.H. Babbitt ‘College Words and Phrases’ in DN II:i 49: plug, n. A slow, disagreeable person.

7. (US) a hard-working but materially unsuccessful person.

[US]J. London Valley of the Moon (1914) 174: There was two kinds of us, the lions and the plugs. The plugs only worked, the lions only gobbled.

8. a worn-out racing greyhound.

[US]W.R. Burnett Dark Hazard (1934) 239: Tommy Mason [...] he’s got his dogs here. Most of them old plugs, no good.

9. (US) a damaged or malfunctioning object, e.g. an old car.

[US](con. 1949) B.A. Mason ‘Detroit Skyline 1949’ in Shiloh 41: We’ve still got that old plug, but it gets us to town.
[US]S. King Christine 63: I looked at the car again, the ’58 Plymouth, sitting in here when it should have been out back in the junkyard with the rest of Darnell’s rotten plugs.