Green’s Dictionary of Slang

briar n.

(US Und.)

1. a burglar’s tool, a file, a saw.

[US]H. Tufts Autobiog. (1930) 292: Briar signifies a saw.
[US]Ladies’ Repository (N.Y.) Oct. VIII:37 316/1: Briar, a file.
[US](con. 1950-1960) R.A. Freeman Dict. Inmate Sl. (Walla Walla, WA) 17: Briar – a saw for cutting bars; a hacksaw blade.

2. a hacksaw blade.

[US] ‘Jargon of the Und.’ in DN V 440: Briar, A thin hack-saw blade with which a convict may saw the bars of his prison.
[US]D. Clemmer Prison Community (1940) 330/2: briars, n. Hack saws, used in reference to sawing bars in jail or prison.
[US]Goldin et al. DAUL 34/1: Briars. Hacksaw blades. ‘Plant (conceal) briars in the soles of your shoes in case you get a drop (arrest).’.

SE in slang uses

In compounds

briar-breaker (n.) (also briar-hopper, brier-heister, brier-hopper) [heister n. (1)]

(US) a rustic, a peasant, an unsophisticated person.

M.E. Davis Wire Cutters 85: Billy Crouch was a briar-breaker, that is to say, one of the pioneers in the settlement which bore his name.
[US]E. Cunningham Triggernometry (1957) 189: The worst old ‘briar-breaker’ in Kimble County.
C.F. Harris Microphone Memoirs 205: Some bedeviled pixy had wished upon us the original hill-billy, the nascent ‘briar-hopper’ of the Barrens.
[US] ‘More Tennessee Expressions’ in AS XVI:1 Feb. 447/1: briar hopper. Dirt farmer. ‘Tilman’s jist a plain briar hopper.’.
[US] in DARE I 380/1: Brier hoppers Poor hill folk (hillbillies) who come into Ohio from Kentucky and west Virginia to make money. Usually live on credit.
[US] in DARE I 380/1: (Names and nicknames for a rustic or countrified person) Brier hopper [...] Brier heister.
[US] in DARE I 380/1: Brier hopper.
King Oscar [Masonic] Lodge 855 ‘Temple Topics’ Jan. 🌐 November’s column indicated that I had never learned from the Grand Master if he was a ‘hillbilly’ or a ‘brier hopper’ when whelped in his native Kentucky.

In phrases