Τζάκετ is a Greek (English) word too. But ζακέτα is different than τζάκετ. Google a little to see some photos of both.
Μπουφάν is more general, I think, than τζάκετ, but I am not sure about.
But ζακέτα even a similar word is a cloth lighter than μπουφάν or τζάκετ.