underachiever
Concise Oxford English Dictionary © 2008 Oxford University Press:
underachieve/ʌndərəˈtʃiːv/
▶verb do less well than is expected, especially in school work.
– derivatives
underachievement noun,
underachiever noun.
underachievement noun,
underachiever noun.
'underachiever' also found in these Oxford entries:

