Another example that springs to mind is the Japanese turning Cook (as in the job) into コック。 which often sounds like a male body part. "his job is ****".

More recently, I was grading papers at the Juku I work at and quite a few students had put the Japanese meaning of "cunning" instead of the English. The English form being an adjective meaning "crafty or tricky", while the Japanese is a verb meaning "to cheat" i.e. on a test. And our Japanese teacher often says "カンニングしないでください。" just before we have to take a test... which threw me the first time I heard it.