E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Shave.
To shave a customer. Hotten says, when a master-draper sees anyone capable of being imposed upon enter his shop, he strokes his chin, to signify to his assistant that the customer may be shaved.
1
I shaved through; he was within a shave of a pluck. I just got through [my examination]; he was nearly rejected as not up to the mark. The allusion is to carpentry.
