What is gabardine?

gaberdine is an article of clothing. Gabardine is a fabric.

"OH, I'm out there, Jerry. There's nothin' between you and me but a thin layer of gaberdine."

In The Merchant of Venice, Shylock berates Antonio for, amongst a list of other nasty stuff, spitting upon his "Jewish gaberdine", meaning his large cloak. Not just the once, this spitting happened, but many a time and oft, apparently.