there are words out there that have clearly missed the mark:
"crampon" for instance, is immediately recognizable as the linguistic offspring of cramps and tampon and, rather than helping you climb mountains, looks like something that would much prefer you to lie quietly on the couch with a hot water bottle and a nice cup of tea instead.
"mentor" is sneaky - it hides one of its unpleasant prefixes ("de-" or "tor-") and stands casually in front of a nondescript white van, offering to help. all i'm gonna say is, DON'T DO IT! DON'T GET IN! it'll end very very badly.
"gastrique," seen recently in food blogs and finer restaurants, is meant to tempt your taste buds. unfortunately, instead of caramelised-sugar-based sweet and sour sauce, it clearly evokes the stuff you bring up once you've emptied your stomach contents but the heaves won't stop.