turtle, n. — Green’s Dictionary of Slang

turtle n.

1. a veteran.

1896

‘Frederick Benton Williams’ (H.E. Hamblen) On Many Seas 96: He [...] swore to the other old turtle that we were the two best and smartest boys he had ever seen.

2. (US) a racehorse (presumably slow).

1901		‘Hugh McHugh’ Down the Line 14: I confided to her the fact that I doped a turtle named ‘Pink Toes’ to win the next day.
1905		‘Hugh McHugh’ Get Next 24: Every turtle we plunged on carried our money to the bonfire and dumped it in.

3. (orig. Aus.) a promiscuous woman [i.e. ‘once she’s on her back, she’s fucked’].

1942		S.J. Baker in Le Courrier Australien (Sydney) 5 June 5/1: A girl or young woman to us is a sheila [...] shingler, sninny, turtle, pross or tarry rope.
1966		Trimble 5000 Adult Sex Words and Phrases.
1984		Partridge DSUE (8th edn) 1275/2: C.20.

4. (N.Z. prison) a 200mg tablet of morphine sulphate.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 194/2: turtle n. a 200mg morphine sulphate tablet.

SE in slang uses

In compounds

turtle shit (n.) [shit n. (4a)/shit n. (3d)] (US)

1. nonsense, rubbish [var. on bullshit n. (1)].

1996

P.J. Jason ‘Assaulting the Net’ on Scroll.org 🌐 You chickenhead piece of shit, you thought you were so fucking great tonight, you felt you played your part so well, you are a piece of dead turtle shit, you’re not a star, you fucking limp dick/pussy hair, dazzling and charming (YOU?), you let me put my brown in your mouth, you’re nothing to behold, you dog vomit, I piss on you.

2. stuffing, the daylights, the insides.

c.2003

‘Rev. of American Streetfighter’ at BadMoviePlanet.com 🌐 He has flashbacks about things that happened after Viper kicked the turtle shit out of him, but its not explained til near the end.

In phrases

go like a herd of turtles (v.)

see go like a rabbit under rabbit n.¹

go turtle (v.) [? the image of a turtle waving its impotent legs after being placed on its back]

(Aus.) to lose emotional control.

1914

Sport (Adelaide) 3 July 4/3: Erry P. almost went turtle when he heard his name was in ‘Sport’ .