See more synonyms for underachiever on Thesaurus.com
  1. a student who performs less well in school than would be expected on the basis of abilities indicated by intelligence and aptitude tests, etc.
  2. a person or thing that performs below expectations.

Origin of underachiever

1945–50; under- + achiever
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Word Origin and History for under-achiever

also underachiever, 1953, from under + achiever (see achieve). Under-achievement is recorded from 1951.

Online Etymology Dictionary, © 2010 Douglas Harper