The answer of Thomas is very good already, and covers many aspects. I just want to add one more aspect which I perceive in the word Körperklaus: I think, besides denoting a person who does move in an uncommon or unhandy way, it can also denote a person which is very beefy, in a way which is perceived as "unnatural", so for instances men practicing a lot of body building. The pejorative connotation is still there, but the denotation is different.
There is a song of the German dancehall band Seeed named Waterpumpee released in 2002 which has the following lines:
Geh bloß uns nicht auf'n Sack,
weil du feige bist zu tanzen,
zieh die teure Jacke aus, du Körperklaus,
zeig, was kannst'n!
Wir moven gut in jedem Look,
im freshen und verranzten,
du mit deinem Benni Miles
schockst die Vorstadtpomeranzen
The song describes an aggressive type of person who is addressed as "Körperklaus", and who is described to meet some stereotypic attributes of masculinity, including lone-wolf-behavior, fetish for brand clothing and a culture focussed on body shape, and contrasts it with a social, "cool", i.e. relaxed type of persons (the lyrical "us") who know how to express their feelings by dancing and get relaxation and a social sense from that dancing.