At first sight, the term
high concept seems to suggest
high-mindedness, but the two concepts could not be more directly opposed. In film terminology, a high concept film is one that can be easily summed up in a single short sentence, based upon a single idea.
Often, the concept behind a high concept film seems to spring from a "what if" question. E.g., the film Big, starring Tom Hanks attempts to answer the question "what if a little boy suddenly became a grown man?" The high concept that was probably pitched at the pitch session is "A little boy becomes a grown man." Hollywood executives are reputed to love this sort of high concept pitch, which is why complex and unclassifiable films are so hard to get produced.
Hollywood film terminology seems to frequently misuse the world high. At least, the Hollywood usage is often counter-intuitive. In the case of "high concept," the "high" seems to mean "at the forefront" rather than "lofty" or "noble."
For another example of the misuse of the word high, consider "high-key lighting," a style of lighting in which the key light is generally low, or at least not as high as it usually is in low-key lighting.