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.
彼女は息子が学校で成果を上げていないと信じています。それは彼が科目に興味を持っていないためです。