It's not an English word. I have never heard it. Where did you get it from? Also in that sentence it wouldn't have an 's' at the end as it's the 'they' form of the verb.

If it's "shank," are you reading the Maze Runner? In that book they have some made-up slang -- words invented by the author that are only used by the Gladers in this book. They use the word shank to mean guy or mate.