/ Dictionary / Index U underachiever: Meaning and Definition of Find definitions for: un•der•a•chiev•er Pronunciation: (un"dur-u-chē'vur), [key] — n. 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. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: underachiever (Thesaurus) underachieve underact Related Content Daily Word Quiz: fabricate Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language