To be skilled or an expert in a field. Well advanced in your chosen field or avocation. Very good and what you do.
What does it mean to be "proficient?"
To be at the expected level for something, not above or below expectations. Meeting the minimum requirement to be qualified for something or to be at a satisfactory level of things such as reading, writing, math or science.
the expected level for something, not above or below goals. Meeting the smallest need to be qualified for something or to be at a appropriate level of aspects such as learning, writing, statistical or technological innovation.