I'd assumed sneap was a word of the Potteries, the famous group of towns in Staffordshire, England which is the setting for Clayhanger. But if I'd been paying more attention I'd have noticed that Shakespeare uses sneap, too. But then Shakespeare came from Stratford (that's Stratford upon Avon: it's nothing to do with either London or the Olympics), which isn't very far away from the Potteries.
It turns out that there are two sorts of sneap. One means to blast with cold (this isn't easy in England at the moment. Actually, though, come to think about it, putting a dahlia in the freezer would sneap it. Though such an action would admittedly be completely bonkers).
This use of sneap is from Shakespeare's play Love's Labour's Lost**:
FERDINAND: Biron is like an envious sneaping frost,
That bites the first-born infants of the spring.
The second meaning of sneap is to rebuke, and that's the meaning that is still used today in the Potteries.
Shakespeare uses this meaning, too.
This is from Henry IV Part 1:
Lord Chief-Justice: Pray thee, peace. Pay her the debt you owe her, and unpay the villainy you have done her: the one you may do with sterling money, and the other with current repentance.
FALSTAFF: My lord, I will not undergo this sneap without reply.
Falstaff by Eduard von Grützner
So there we are. I've learned a new word. Am I going to sneap myself for not noticing it before, even though I studied Henry IV Part 1 for A Level?
Nope. These discoveries give one an illusion of increasing wisdom, after all.
Thing Not To Do Today: be sneaping. This word is probably from Scandinavia. It's quite like the Icelandic sneypa to scold.
*By the way, Clayhanger is another trilogy consisting of four books.
**The title in the First Folio doesn't have any apostrophes. Or, actually, a u in Labour.