"A bit thin" is a commonly used phrase to describe something that lacks substance or fullness. However, there are numerous synonyms that can be used to better convey this meaning. Words like meager, sparse, skimpy, scanty, and inadequate all suggest a lack of quantity or quality. Similarly, words like lean, skinny, bony, lanky, and gaunt imply a lack of thickness or robustness. These synonyms can be used in a variety of contexts, from describing a meal that is small and underwhelming to a book that is lacking in detail or substance. By utilizing these synonyms, writers can add more depth and precision to their language.