quatschkopf
Originates from German "Quatschkopf". Commonly used incorrectly, referring to babbling idiots. Quatschkopf rather means someone who talks a lot about unimportant things. A talky person. However, contrary to most definitions in online dictionaries, it is a rather nice and positive thing to say, at least in Southern Germany. If you tell someone he/she is a quatschkopf, your heart is full of appreciation and sympathy. Quatschkopfs generally tell something that doesn't really fit the context, and especially for that they are amiable - there is something sweet about them. Using the word usually makes people smile; both the 'quatschkopfer' (the one calling someone else a quatschkopf) and the 'quatschkopfee' (the person being called a quatschkopf). Also, quatschkopf can be used as a verb: to quatschkopf someone means to babble nice nonsense to someone.

Side note: should only be used when speaking to the quatschkopf. If used when referring to someone, one has to know that someone very well in order to avoid a negative connotation.
You are a quatschkopf.

Sometimes my brother can be a real quatschkopf.

Man, today you are quatschkopfing me...

That sweet person was quatschkopfing me the whole night long.

I was quatschkopfed, and didn't see it coming.