I was about to refer this query to English/implausible, because in English it is used, but in Spanish it does not exist. And it turns out I thought it over; it is not incorporated into the dictionary, but it has a correct conformation, a Latin origin, a positive version and I can not find a reason to exclude it from this dictionary (come on, i have defined every extravagant neologism). So let's say that implausible is something that you can't applaud, that you can't approve or encourage, that you don't have our consent, and as a second meaning that's not credible, that would be a good reason to disapprove. It is formed by the negative particle in , converted to im, followed by plausible.