n. An achievement that is less than expected; underperformance.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. poorer than expected performance (poorer than might have been predicted from intelligence tests)
Word Usage
"One year later the Downing Street policy unit concluded, in a report entitled Ethnic Minorities and the Labour Market, that “the old picture of white success and ethnic underachievement is now out of date”."