If the more advanced want to improve English ability (especially reading comprehension) increasing vocabulary is the way to go.

For example, I am in a high-level math class that actually gives me college credits for next year.

The defendant will appeal to a higher court.

He appealed to a higher court against the decision.

Senior executives spend a lot of time training their subordinates.

Senior students have access to the library at weekends.

This dictionary is useful to beginners, yes, and to advanced learners.

Tom is a pretty good snowboarder.