- a student who performs less well in school than would be expected on the basis of abilities indicated by intelligence and aptitude tests, etc.
- 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
Online Etymology Dictionary, © 2010 Douglas Harper