The phrasal verb "brush up" is primarily used in informal contexts, though it can also appear in more formal speech or writing, particularly when discussing skills or knowledge. It generally means to review, refresh, or improve one's understanding or abilities in a particular area that may have become rusty or neglected. Common usage patterns include contexts such as studying for a test, refreshing language skills, or revisiting forgotten hobbies. For example, someone might say "I need to brush up on my French before the trip to Paris." The phrase suggests an action that is not intensive or ground-up learning, but rather a polishing of previously acquired skills or knowledge.
B2
UpperIntermediate
1. To improve or refresh one's skills or knowledge by study or practice.
I need to brush up on my Spanish before the trip to Mexico.
She's brushing up on her cooking skills for the competition.