Green’s Dictionary of Slang

pineapple n.1

1. (also Niagara pineapple) a bomb, a grenade [the shape].

[UK]B.E.F. Times 25 Dec. (2006) 140/1: A lump of pineapple gone t’rough the rum jar.
[UK]Hall & Niles One Man’s War (1929) 331: Those goddamned pom-poms! Or, as the British call ’em, ‘flamin’ pineapples!’.
[Aus](con. WWI) A.G. Pretty Gloss. Sl. [...] in the A.I.F. 1921–1924 (rev. t/s) n.p.: pine-apple. A light German trench mortar shell, grooved into sections to ensure a fragmental burst.
[US]Hostetter & Beesley It’s a Racket! 25: Tossers of bombs took orders for ‘pineapples,’ then ‘went into production,’ and finally placed them for explosion.
C.B. Yorke ‘Snowbound’ in Gangster Stories Oct. n.p.: There was a stunning roar of an explosion [...] Suds Garland’s mob had tossed a pineaple into the entrance hall!
[US]Public Enemy [film script] Look at this dump — four pineapples tossed at us in two days.
[UK]G. Kersh Night and the City 120: Four men in a car, with pineapples, and Tommy-guns, and tear-gas, and sawn-off shotguns, and gats, and rods, and heaters and razors.
[US]Black Mask Mar. XXII 13: That guy, Soup, is kill-crazy. He might toss a pineapple at us.
[US]Monteleone Criminal Sl. (rev. edn) 162: niagara pineapple A tear gas bomb.
[US]A.J. Liebling Honest Rainmaker (1991) 114: A hefty pineapple exploded aft.
[US]Ragen & Finston World’s Toughest Prison 812: pineapple – A bomb.
[US]L. Heinemann Close Quarters (1987) 39: A [...] claymore bag filled grenades, both the old pineapples and the newer smooth-sided sort.
[US](con. 1967) Bunch & Cole Reckoning for Kings (1989) 65: Lying on the packed dirt floor was an elderly World War II pineapple-type hand grenade.

2. attrib. use of sense 1.

[US]W.N. Burns One-Way Ride 269: His pineapple brigade had bombed half a dozen saloons.

3. a male homosexual [play on fruit n. (2)].

[UK]A. Bleasdale It’s a Madhouse (1986) 127: An’ I don’t care what the pineapple in there says, I am y’know, I’m sick.
[UK]Partridge DSUE (8th edn) 886: [...] since ca. 1960.

4. (US) a Puerto Rican [the jungle associations].

[US]H. Gould Fort Apache, The Bronx 35: He’d run through his whole repertoire on the ‘boots and the pineapples’, the current precinct names for blacks and Puerto Ricans.

5. (US campus/drugs) heroin [ety. unknown].

[US]Eble Campus Sl. Apr. 5: smack – heroin. Also pineapple.

6. (Aus.) a $50.00 note.

[Aus]T. Peacock More You Bet 67: The ‘$50 note’ is sometimes referred to as [...] a ‘pineapple’, due to its colour.
[Aus]N. Cummins Tales of the Honey Badger [ebook] I owed a pineaple to the old man.

SE in slang uses

In compounds

pineapple head (n.) [-head sfx (2); the jungle associations]

a derog. term for a Samoan American.

[UK]Indep. 2 Oct. 5: Police had referred to them contemptuously as ‘coconut head’ and ‘pineapple head’.