Green’s Dictionary of Slang

1. any form of difficulty; a fight.

1833		C.A. Davis Letters of Major J. Downing (1835) 190: If the country don’t prosper, or if it gits into a snarl, they lose their mony.
1843		W.T. Thompson Major Jones’s Courtship (1872) 24: Things is in a most bominable snarl down here.
1865		Leaves from Diary of Celebrated Burglar 43/1: A snarl was the consequence between Selina and her ‘dress lodger,’ and she was quickly told to ‘peel’ off her ‘togs’ and ‘namase’.
1877		R. Burdette Rise and Fall of the Mustache 107: We don’t believe all Burlington could have pulled us out of that snarl.
1930		Eve. Teleg. 12 Feb. 6/4: The tailor who loves argument (‘snarl’) is after all only a ‘bunch of snarls’.
1956		C. Chessman Trial by Ordeal 268: The curious legal snarl confronting me.
1958		Tampa Trib. (FL) 30 Jan. 10/5: A complete snarl-up in federal government bureaucrac yesterday.
1966		D. Ward Day of Absence in Black Drama 190: supervisor: What’s the snarl-up? first operator: Everybody calling at the same time, ma’am!
1970		Times 12 Feb. 25: Freight business is healthier, but still recovering from nightmare snarl-ups that followed the merger.

2. (orig. US) a traffic jam.

1961		Aberdeen Eve. Exp. 13 July 10/4: Snarl Up. The traffic had begun to snarl up.
1970		G.F. Newman Sir, You Bastard 24: Sneed [...] couldn’t care less what snarl-ups the lorry caused.
1999		Guardian G2 19 Oct. 3: I take the old A5 back down to London rather than chance a snarl-up on the middle-aged M1.
2010		Republic (Columbus, IN) 25 Aug. 6/1: Triggered by road construction, the snarl-up [...] was 60 miles long.