What's "keep fit" mean? And isn't "fit" similar to "suitable?"

Native speaker’s answer
Rebecca
You're right. "Fit" can mean suitable! However, here it means healthy or in good shape. Implying that the person exercised. So, "keep fit" means to continue to stay or work on being "fit." Ex: I'm not sure how I'm going to keep fit while in quarantine. Ex: She kept fit by joining a local football club, going on jogs, and eating well.