Highbrow can be used as a noun to describe an intellectual but can also be used adjectivally as in highbrow literature. It is an Americanism that dates from the late 19th/early 20th century and became Standard English by the time of the First World War. It derives from the allusion (or perhaps illusion) that people with high brows or large foreheads possess more brains. Its anonym, low-brow, came into use a little later. See also egghead.