late 14c., in anatomical and mathematical uses, "of or relating to a surface," from Late Latin superficialis "of or pertaining to the surface," from superficies "surface, upper side, top," from super "above, over" (see super-) + facies "form, face" (see face, n.). Meaning "not deep, without thorough understanding, cursory, comprehending only what is apparent or obvious" (of perceptions, thoughts, etc.) first recorded early 15c. (implied in superficially "not thoroughly").