Ruby, 41 words

True self, do not begin class break, end class break, ensure class break, redo and redo class break, retry class break, rescue class break, or yield class break, until next class end (or next class module or next class return), or else!

Ruby, 41 words

True self, do not begin class break, end class break, ensure class break, redo and redo class break, retry class break, rescue class break, or yield class break, until next class end (or next class module or next class return), or else!

That's just using words listed as actual keywords. There are a lot of other words that act like keywords because they're methods of the kernel or instance methods of Class.

A cheesier approach would start

Do not def "alias","begin","break",...