The traditional Boggart is not quite as interesting as the one found in Harry Potter, which turns into whatever you fear the most so that no one really knows what it looks like. Rowling’s Boggart is defeated with laughter, but the genuine article is neither quite as scary, nor quite as easy to deal with.
Boggarts in traditional English legend are a malevolent kind of household fairy. These creatures spoil milk, make dogs go lame (poor things!) and perform nasty tricks like making things disappear or stealing your sheets while you’re sleeping.
In Northwest England, it is believed that boggarts live underneath bridges or near sharp (pointedly dangerous) curves in roads, and it is custom to pay your respects to the boggart while passing by—in order for it to let you do so safely.
The one defense really against a boggart is to move from the house it resides in, but some boggarts may actually follow you! Whatever the case, do not name your boggart. If you give it a name, a boggart becomes completely unmanageable. If you were ever able to manage it in the first place, that is. 😉