If you're looking for other ways to express the phrase "keen about," here are some synonyms to consider. "Enthusiastic about" denotes a strong and eager interest, while "zealous about" suggests a deep devotion or passion for something. "Obsessed with" conveys an almost excessive and preoccupied level of fondness. "Fascinated by" implies a strong attraction to something in an inquisitive way, while "interested in" simply expresses curiosity or desire to learn more. "Passionate about" is an intense form of enthusiasm, and "devoted to" expresses dedication and loyalty towards a particular subject or activity.