This is the 656th most frequent Japanese word.
買う
To buy.
This is a regular polite past-tense usage of '買う' (to buy), indicating the action was completed.
私は新しい本を買いました。
I bought a new book.
Here, '買う' is part of the compound noun '買い物' (shopping), showing its derivation and usage in creating related terms.
週末に友達と一緒に買い物に行く予定です。
I plan to go shopping with my friend on the weekend.
This demonstrates usage of '買う' (to buy) in the dictionary form within a phrase suggesting advice or guidance.