"Low-res" was slang for a person considered to be contemptible or of low social standing, synonymous with the term "low-life". When Martin McFly Jr. was arrested for robbery of the Hill Valley Payroll Substation, Griff Tannen stated in an interview that McFly was too "low-res" to be associated with them.
Behind the scenes
Alluding to a computer generation, the term is a shortened form of "low resolution" which usually indicates an image with poor quality. It was later then used as a slang term for someone of that nature.
- Back to the Future Part II (in Youth Jailed newspaper article)