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.
她認為她的兒子在學校表現不佳,因為他對這些科目沒有興趣。