Sonnyboy, der

This is one of the great pseudo-Anglicisms, as it is often unquestioningly employed by bilingual people. It refers to a male who radiates smiling charm. Die Sonnyboys are mostly aged between 20 and 50. The term has for example been applied in 2008 to Jürgen Klinsmann, the coach of the Bayern München football team, in praise of his amiable grin and ability to get people on his side. Der Sonnyboy is not always a positive character: he may even be a con artist. But you can't help liking the guy. We don't really have an equivalent expression in English.
Der Sonnyboy is capitalized, given masculine gender, inflected with -s- in the genitive and is sometimes spelled der Sunnyboy though the Duden prefers the spelling with -o-. Its origin is a complete mystery.