The only really important thing to know about hypallage is that you say it hi-PAL-er-jee.
Yes, that's right, it's Greek.
Although hypallage isn't very important, it is interesting because quite often it involves giving an emotion to the owner of the thing who's actually experiencing it.
Roberto raised his angry sword is an example.
Or Sharon ran a covetous hand over the silk petticoat.
Or - not to be sexist about it - Sharon raised an angry sword, and Roberto ran a covetous hand over the silk petticoat.
(It is much more interesting that way round, isn't it.)
These are obvious examples, but hypallage is used all the time. If you've ever spent a wakeful night, or drank a thoughtful glass of wine, you've been using hypallage.
The most important thing about it is the idea of exchange: that you're pinning a description or an action on something, well, technically wrong. Or you might be switching round two words to make a point. The example in my Collins dictionary is the fire spread the wind.
Anyway, it's nice to know we're all masters of hypallage, isn't it.
Let's face it, it's impressive enough just that we can pronounce it.
Nuts and Bolts: hypallage. This word comes from hyper- from the Greek huper, above, and the other Greek word allassein, to exchange.