(From a pun
on the Yiddish M'ken zi
, "We know her".)
Leo Rosten notes in Hooray for Yiddish! that the Yinglish term McKenzie has been used in three distinct senses:
- Someone who browses all the time but never buys anything.
- A shoplifter; Jewish shopkeepers sometimes used the code word "Mrs. McKenzie" to alert staff that a known gonef was on the premises.
- A promiscuous woman. (This appears to be a play on the Biblical sense of "we know her".)
So far as I can tell, the term is not generally understood as a slur against any Scot with this surname -- it's just a pun.