/ Dictionary / Index B brain truster: Meaning and Definition of Find definitions for: brain' trust"er Pronunciation: [key] a member of a brain trust; an important but usually unofficial adviser. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. brain trust brainwash Related Content Daily Word Quiz: secular Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language