Urbandictionary.com says it means:
To rob. Verb. Present tense of juxt.
It has 342 votes but I can’t find any evidence of actual usage on a google or COCA search.
The verb to jux as used in New York does mean to rob, for example to rob someone is to jux a head.
Here’s a couple of sentences from the book Lush Life by Richard Price where he uses the word jux. Actually the word appears 8 times in the novel. From that it seems to me that it is a “real word” used in NYC.
“Most project are kind of like, that’s all they know, but you go two blocks in any direction from here, you go Wall Street, Chinatown, the Lower East Side, they are like release valves, you know? They give you the confidence to mix it up in the world -“
“And jux everybody in sight,” Iacone murmured.
“You’re so cynical, I swear to God,” Yolanda said. “I was a projects kid, I didn’t jux anybody”
“How about a running buddy? Somebody he likes to jux heads with out there.”