1. Somebody who doesn't quite do as is generally supposed to, often in a clever or
cunning way.
2. Also can be used as an
insult for anybody
disliked, whether they are fiendish or not.
1. That criminal was very fiendish in stealing the
Queen's purse.
2. Some guy I know called Carwyn, he's Welsh/Belgian/Dutch/English. Generally rather
moronic.