verb (used without object), un·der·a·chieved, un·der·a·chiev·ing.
to perform, especially academically, below the potential indicated by tests of one's mental ability or aptitude.
to perform below expectations or achieve less than expected, especially by others.
Origin of underachieve
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
(intr) to fail to achieve a performance appropriate to one's age or talents
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012