1. To diminish or reduce in value.
2. To render into a crap-like state.
3. To cover or fill with crap.
I hope those scissor-monkeys over at Spiffy-Cuts don't encrappen my hair.
The recent spate of mortgage defaults is encrappening the credit markets.
To make something crap, or crapper than it previously was.
Alice: hey, did you hear that faceborg has launched a commenting plugin?
Bob: yeah, now all the fuckwits I went to high-school with can encrappen my stream with their banal comments about crap they watch on TV.