Propeller-head is a slang term used to describe someone who is highly intelligent and knowledgeable in a particular field. It is often used as a derogatory term to describe someone who is overly obsessed with a certain topic or activity. The terms DWEEB and NERD are also used to describe someone who is highly intelligent and knowledgeable, but they are not necessarily used in a derogatory manner. DWEEB is a five letter word that is used to describe someone who is socially awkward and overly studious. NERD is a four letter word that is used to describe someone who is highly intelligent and knowledgeable, but is also seen as socially inept.