rat pack, n. — Green’s Dictionary of Slang

rat pack n.

[best known of such gangs are Hollywood’s Holmby Hills Rat Pack whose members included not juveniles but such stars as Humphrey Bogart and its successor, the Rat Pack, led by Frank Sinatra, Dean Martin et al. (which group had formerly been known as The Clan]

1. (US) a juvenile or prison gang.

1951		R.S. Prather Bodies in Bedlam 65: It looked like three or four of L.A.’s juvenile moron gangs, sometimes called rat packs, had taken turns going over the place. It was thorough .
1974		H.L. Foster Playin’ the Dozens 91: More recently, gangs, fraternities, cliques, organizations, and ‘rat packs’ have again begun to be reported.
1989		H. Rawson Dict. of Invective (1991) 323: rat pack. A gang, originally teenage use.

2. a group of sycophants, hangers-on.

1948		N. Nye Breed of the Chaparral (1949) 103: There’s no good reason when any man should worry what appens to the rat-pack you’ve brought in here with you, but any time you want to make this thing less messy, just get on your feet and we’ll slug it out between us.
1969		D. Pendleton Executioner (1973) 40: I’ll shoot dead in his tracks any man who tries to turn this squad into a ratpack.
1972		J. Reid speech at Glasgow U. 🌐Before you know where you are, you’re a fully paid-up member of the rat pack.
1989		H. Rawson Dict. of Invective (1991) 323: The Hollywood rat pack, led by Frank Sinatra.
1999		Guardian Guide 26 June–2 July 6: You date starlets, receive Oscars and take your travelling rat pack in a party across the globe.
2000		P. Beatty Tuff 111: Winston turned to face Clifford and his rat pack.

3. (US black) an attack by a gang.

1988

NWA ‘Gangsta Gangsta’ 🎵 A bum rush, but we call it rat pack.

4. (N.Z. prison) the riot squad.

2001

D. Looser Boobslang [U. Canterbury D.Phil. thesis] 151/2: rat pack, the n. the Riot Squad.