Q From Jane Rawoof: What is the origin of the phrase up to snuff?
A The snuff here is tobacco: nothing to do with the verb meaning to extinguish. Several colloquial phrases are recorded that used the word snuff, most of which date from the early part of the nineteenth century in Britain, when snuff-taking was still common, but less fashionable than it had been fifty years before.
The first meaning of up to snuff was somebody who was sharp, not easily fooled. This may have come from the idea of snuff being itself a sharp preparation, but perhaps because it was mainly taken by men of adult years and some affluence (it was expensive) who would be able to appreciate the quality of snuff and distinguish between examples of different value. The evidence isn’t there to be sure about its exact origin, though an early form of the phrase was up to snuff and a pinch above it, which at least confirms it did indeed relate to tobacco.
Whatever its origin, the meaning of the phrase shifted slightly after a while to imply somebody who was efficient and capable; later still it often meant that something was up to standard, or of the required quality. It was in this sense very similar to another expression of the time, up to scratch. This comes from prize-fighting, in which the scratch was the line across the floor that a contestant had to touch with his toe to indicate he was ready to fight.