"Swotted up" is a common phrase used to describe someone who has studied or researched a topic in-depth and has become knowledgeable about it. Some synonyms for this phrase include "crammed," "memorized," "acquainted," "familiarized," "competent," "proficient," and "versed." Other similar phrases could be "brushed up on," "mastered," "studied diligently," "put in the hours," and "immersed oneself in." No matter which term is used, the implication is that the person has invested time and effort into learning about a specific subject matter and has a strong understanding of its concepts and principles.