Fockhead

A fockhead (or a "fock" for short) is someone who is both unbelievably useless and a waste of time and space. That's it. It derives in scientific circles, at least, from "Fock Space" which in physics is an algebraic construction for Quantum States. For those nerds who have studied physics the Fock Space construction is an incredibly complicated development of Hilbert space and of only tangential utility. (Please Wikipedia "Fock Space" for more information on the Fock Space in physics). In a word it is someone who exhibits a humorously-to-irritatingly useless way of thinking. So when people (mostly physics students) call someone a "fockhead" they are suggesting they are absolutely useless and a waste of time. Disclaimer: It does not originate from the similar sounding swearword, "f-u-c-k", though it can sound similar to the non-scientifically literate so unsurprisingly it's most commonly used privately in scientific circles.