Old-school cool is a term used to describe something that is considered fashionable or popular from the past. The two crossword solutions for this term are NEATO and HEP. NEATO is an acronym for 'Not Even A Theory Of Everything' and is often used to describe something that is cool, neat, or impressive. HEP is an acronym for 'Highly Energetic Person' and is often used to describe someone who is stylish, fashionable, and up-to-date with the latest trends.