underachieve
🇺🇸
/ˌʌndərəˈtʃiːv/
🇬🇧
/ˌʌndərəˈtʃiːv/
to not perform as well as you are capable of, particularly in an academic setting
She believes her son is underachieving at school because he's not interested in the subjects.
她认为她的儿子在学校表现不佳,因为他对这些科目不感兴趣。