Flatties is a colloquial term used to describe shoes with flat soles. While this term may be commonly used, it is always good to have a variety of synonyms in your vocabulary. Here are a few alternatives that you can use: flat shoes, ballet pumps, loafers, slip-ons, moccasins, skimmers, dolly shoes, ballerinas, sandals, and trainers. Each of these words denote a form of footwear that lacks any form of elevation. When looking to get dressed for a casual or semi-formal occasion, any of these alternatives will help minimize the negative connotation that could come with using the term "flatties".