Search Result for "underachievement": 
Wordnet 3.0

NOUN (1)

1. poorer than expected performance (poorer than might have been predicted from intelligence tests); 



WordNet (r) 3.0 (2006):

underachievement
    n 1: poorer than expected performance (poorer than might have
         been predicted from intelligence tests) [ant:
         overachievement]