A portmanteau of the abbreviation LA, for Liberal Arts, and 'tard. Pronounced "lay-tard", LAtard is a pejorative term for a person studied in the Arts and Humanities. They typically believe themselves to be more "cultured", "creative", "open-minded", and "erudite" than most people but lack the skills to work a basic calculator, let alone engineer a bridge.
Not to be confused with Libtard.
There's a flame war between the LAtards and STEMlords on Reddit again.